Antifoaming agent compositions, water-based paint compositions and articles

Abstract

The present invention provides an antifoaming agent composition capable of forming a coating film with excellent painted appearance, possessing excellent shear resistance, and not impeding topcoatability; a water-based paint composition containing this antifoaming agent composition; and an article coated with a coating agent containing this antifoaming agent composition. [Solution] The defoaming agent composition for water-based paints comprises a nonionic surfactant (A) having at least one hydrophilic portion selected from the group consisting of an ethylene glycol portion, a polyethylene glycol portion, and a polyhydric alcohol portion in its molecule, and having an HLB of 1 to 16; a polymer (B) that does not have the hydrophilic portion in its molecule, has an SP value of 7.5 to 12, and a weight-average molecular weight of 400 to 1,000,000; and organic solid fine particles (C) that are in a solid state in the defoaming agent composition at 25°C.

Description

[Technical Field]

[0001] The present invention relates to an antifoaming agent composition, a water-based paint composition, and articles. [Background technology]

[0002] In recent years, there has been a growing emphasis on the appearance of painted surfaces in the field of water-based paints. Since air bubbles remaining in the paint film during application significantly impair the appearance, the performance requirements for defoaming agents added to paints have also increased in line with this recent trend of prioritizing painted appearance.

[0003] Here, as an antifoaming agent that can be used in applications where a high appearance is required, for example, the antifoaming agent described in Patent Document 1 has been proposed. In addition, examples of antifoaming agents with excellent antifoaming effects include silicone-type antifoaming agents (see, for example, Patent Document 2) and compound-type antifoaming agents (see, for example, Patent Document 3). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 4526584 [Patent Document 2] Japanese Patent Publication No. 2001-212403 [Patent Document 3] Special Publication No. 01-6803 [Overview of the project] [Problems that the invention aims to solve]

[0005] Generally, silicone-type defoamers exhibit excellent defoaming properties due to their extremely low surface tension. However, the bleeding of silicone components onto the paint film surface can cause paint repellency and hinder topcoatability. Even if these adverse effects are not observed in short-term laboratory tests or actual painting processes, a single problem in mass production can lead to significant losses. Therefore, silicone-based materials are often avoided in paints used in applications where high appearance is important, such as multi-layer coating systems and large-scale painting systems like line painting. In such cases, the use of silicone-type defoamers is generally discouraged. On the other hand, compound-type defoamers contain fine particles with hydrophobic surfaces, and their high defoaming properties stemming from these hydrophobic surfaces make them frequently used for their superior defoaming effect.

[0006] Incidentally, in recent years, water-based paints often use raw materials that are difficult to disperse in water in order to improve their functionality. Since these raw materials will affect the appearance of the paint if they are not sufficiently atomized or dispersed, in recent years, the dispersion process has been made longer, or the shear force applied to the paint during the dispersion process has been increased (high shear).

[0007] However, the compound-type defoaming agents described in Patent Document 3 and the defoaming agents described in Patent Document 1 may lose their defoaming properties during processes such as long-term dispersion or high-shear dispersion. Therefore, there has been a need for a defoaming agent that has resistance to the defoaming property loss due to the application of shear force to the paint (hereinafter referred to as "shear resistance"). In addition, paints are sometimes circulated to prevent sedimentation and separation of components in the paint, and in such cases, long-term shear resistance is required.

[0008] Furthermore, compound-type defoamers may impair the smoothness and gloss of the paint film due to the presence of fine particles.

[0009] Therefore, the present invention has been made in view of the above circumstances, and aims to provide an antifoaming agent composition that can form a coating film having an excellent painted appearance, has excellent shear resistance, and does not impede topcoatability, a water-based paint composition containing this antifoaming agent composition, and an article coated with a coating agent containing this antifoaming agent composition. [Means for solving the problem]

[0010] The present inventors conducted extensive research to solve the above problems and discovered that by adding a nonionic surfactant having a hydrophilic portion with a specific structure and a specific HLB range, a polymer having a specific SP value and weight-average molecular weight range, and organic solid fine particles as components of the defoaming agent composition, it is possible to provide a defoaming agent composition for water-based paints that can form a coating film with an excellent painted appearance, has excellent shear resistance, and does not impede topcoatability. Based on this finding, the present invention was completed.

[0011] In other words, the present invention is an antifoaming agent composition for water-based paints, characterized by comprising: a nonionic surfactant (A) having at least one hydrophilic portion selected from the group consisting of an ethylene glycol portion, a polyethylene glycol portion, and a polyhydric alcohol portion in its molecule, and having an HLB of 1 to 16; a polymer (B) that does not have the hydrophilic portion in its molecule, has an SP value of 7.5 to 12, and a weight-average molecular weight of 400 to 1,000,000; and organic solid fine particles (C) that are in a solid state in the antifoaming agent composition at 25°C.

[0012] In one embodiment of the present invention, the nonionic surfactant (A) may be one or more selected from the group consisting of ethylene glycol aliphatic ether, polyoxyalkylene aliphatic ether, polyoxyalkylene aromatic ether, polyoxyalkylene fatty acid ester, alkylene oxide addition derivative of castor oil, alkylene oxide addition derivative of hydrogenated castor oil, polyoxyalkylene polyhydric alcohol ether, polyhydric alcohol fatty acid ester, alkylene oxide addition derivative of polyhydric alcohol fatty acid ester, polyoxyalkylene alkylamide, acetylene glycol and its derivatives, alkylene oxide addition derivative of acetylene glycol, polyoxyethylene-polyoxypropylene block copolymer, and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer.

[0013] In another embodiment of the present invention, polymer (B) may be one or more polymers selected from the group consisting of polyvinyl alkyl ethers, polybutadiene, polybutene, polyisoprene, polyalphaolefin, polyalkyl (meth)acrylate, copolymers of dibasic acid esters, polyfatty acid vinyl esters, copolymers of alkyl (meth)acrylate and fatty acid vinyl ester, and polyalkylene glycol derivatives (wherein the polyalkylene glycol derivative does not have the ethylene glycol portion, the polyethylene glycol portion, and the polyhydric alcohol portion, and the weight-average molecular weight of the polyalkylene glycol derivative is 400 to 1,000,000).

[0014] In another embodiment of the present invention, the organic solid fine particles (C) may be one or more solid fine particles selected from the group consisting of amides, ureas, polyethylene, oxidized polyethylene, acid-modified polyethylene, and hydrogenated castor oil.

[0015] In this case, it is preferable that the amide is a fatty acid diamide obtained by reacting fatty acids selected from the group consisting of alkyl fatty acids and hydroxy fatty acids and containing at least one or more hydroxy fatty acids, with diamines selected from the group consisting of alkylene diamines having 2 to 6 carbon atoms and m-xylenediamine and containing one or more diamines.

[0016] In another aspect of the present invention, it is preferable that the aspect ratio of the crystal of the organic solid particles (C) is 1.1 to 100.

[0017] In another aspect of the present invention, the antifoaming agent composition may further contain an organic medium (D) that is liquid at 25°C other than water and does not have the hydrophilic part in the molecule, and the weight average molecular weight of the organic medium (D) may be less than 400.

[0018] In this case, the organic medium (D) may be one or more selected from the group consisting of hydrocarbon oils, alcohols, glycol ethers, and glycol esters.

[0019] In another aspect of the present invention, it is preferable that the antifoaming agent composition does not contain a silicone compound.

[0020] Further, the present invention is an aqueous coating composition characterized by containing the above-described antifoaming agent composition and an aqueous resin.

[0021] Furthermore, the present invention is an article coated with a coating agent containing the above-described antifoaming agent composition.

Advantages of the Invention

[0022] According to the present invention, by including a specific nonionic surfactant, a polymer, and organic solid fine particles as components of the defoaming agent, it is possible to provide a defoaming agent composition that can form a coating film with an excellent painted appearance, has excellent shear resistance, and does not impede topcoatability; a water-based paint composition containing this defoaming agent composition; and an article coated with a coating agent containing this defoaming agent composition. [Modes for carrying out the invention]

[0023] Preferred embodiments of the present invention will be described in detail below.

[0024] [Antifoaming agent composition] The defoaming agent composition according to the present invention is an additive for suppressing the generation of bubbles caused by the presence of various surfactants in water-based paints, and contains as essential components a nonionic surfactant (A) having a hydrophilic portion with a specific structure and a specific HLB range, a polymer (B) having a specific SP value and weight-average molecular weight range, and organic solid fine particles (C). Thus, according to the present invention, it is possible to provide a defoaming agent composition for water-based paints that can form a coating film with an excellent painted appearance, has excellent shear resistance, and does not impede topcoatability.

[0025] Here, "defoaming property" in this invention refers to the ability to eliminate bubbles generated in water-based paints. "Shear resistance" in this invention refers to resistance to the deactivation of defoaming properties due to the application of shear force to the paint, as described above; in other words, it refers to the ability to suppress the deactivation of defoaming agents when shear force is applied to the paint. Furthermore, "overcoating property" in this invention refers to the ability to apply a topcoat to an already applied paint film (hereinafter referred to as "undercoat") in a coating system composed of multiple layers, without causing repelling or other problems, and without problems such as peeling occurring between the topcoat and undercoat. While overcoating property is generally evaluated by creating a multi-layer coating and performing an adhesion test of the topcoat to the undercoat, it can also be evaluated simply by measuring the contact angle of the undercoat surface. When evaluating by contact angle, the liquid used for evaluating the contact angle can be a topcoat paint, or in the case of water-based paints, a co-solvent (an organic solvent blended into the paint), water containing a co-solvent, or simply water. The lower the contact angle of the liquid droplet dropped onto the undercoat film, the lower the topcoatability. The following describes in detail these essential components and the optional components included in the defoaming agent composition according to the present invention.

[0026] (Nonionic surfactant (A)) The nonionic surfactant (A) according to the present invention is an ingredient that exhibits defoaming properties and is added to enhance the penetration of the defoaming agent into the foam film. Furthermore, the nonionic surfactant (A) also functions as a stabilizer to ensure the stable presence of defoaming droplets containing organic solid particles (C), or the organic solid particles (C) themselves, in water-based paints. Note that a surfactant refers to an organic functional agent that has the property of reducing the surface tension of a liquid. For example, hydrogenated castor oil (hydrogenated castor oil), which is a fatty acid triglyceride, is not a surfactant and is therefore not included in the nonionic surfactant (A).

[0027] The nonionic surfactant (A) according to the present invention is a nonionic surfactant having at least one hydrophilic portion selected from the group consisting of an ethylene glycol portion, a polyethylene glycol portion, and a polyhydric alcohol portion in its molecule, and having an HLB of 1 to 16.

[0028] The above-mentioned "hydrophilic portion" is defined as one or more portions selected from the group consisting of ethylene glycol portion, polyethylene glycol portion, and polyhydric alcohol portion, present in the molecule of nonionic surfactant (A). The ethylene glycol portion is the oxyethylene group represented by -CH2CH2O-. The polyethylene glycol portion is -(CH2CH2O) n This refers to a polyoxyethylene group represented by -(n≧2). The polyhydric alcohol portion refers to the portion of a molecule derived from an organic group having two or more hydroxyl groups, when the nonionic surfactant (A) is a derivative of a dihydric or higher alcohol, that is obtained by excluding monovalent substituents and acyl groups composed only of hydrocarbons with one or more carbon atoms, and that does not fall under alkylene glycol or polyalkylene glycol. Furthermore, when the "hydrophilic portion" is composed only of ethylene glycol or diethylene glycol, the number of carbon atoms in the hydrophobic portion (the portion of the nonionic surfactant (A) other than the "hydrophilic portion") is limited to nine or more.

[0029] Furthermore, if the HLB of nonionic surfactant (A) is less than 1, it has poor compatibility with water, which may lead to problems such as the separation of the nonionic surfactant component itself in water-based paints. On the other hand, if the HLB of nonionic surfactant (A) exceeds 16, its affinity for water is too high, which may prevent it from adequately stabilizing other components of the defoamer, potentially leading to problems such as the formation of aggregates or the separation of other defoaming components in water-based paints.

[0030] The mechanism of action of defoamers is known to be that defoamer droplets, which have poor affinity for aqueous media, penetrate the foam film, and when the droplets penetrate the foam film, foam breakage occurs starting from the droplets. From this, it can be considered that substances with high hydrophobicity, i.e., substances with low HLB values, have potentially superior foam-breaking properties. On the other hand, the defoamer droplets must be small enough to penetrate the foam film. For this to happen, a certain degree of hydrophilicity is necessary; the higher the hydrophilicity, the higher the dispersibility in water, and therefore the smaller the droplets become. Conversely, if the hydrophilicity is low, the droplets become larger. If the droplet diameter is too small, it cannot penetrate the foam film, and if it is too large, it cannot penetrate the foam film, and in either case, the defoaming function will not be exhibited. Therefore, there is an appropriate HLB range for controlling the droplet diameter.

[0031] It is even more desirable if the nonionic surfactant (A) is within an appropriate HLB range, as it itself possesses antifoaming properties. From this viewpoint, it is preferable that the HLB of the nonionic surfactant (A) is 2 to 16, and more preferably 3 to 16.

[0032] Furthermore, the nonionic surfactant (A) has the function of homogenizing the other components of the defoaming agent composition of the present invention, namely the polymer (B), organic solid fine particles (C), and organic medium (D), within the defoaming agent composition. In addition, the nonionic surfactant (A) contributes to the expression of defoaming function by controlling the particle size of the droplets formed by the mixture of each component to an appropriate size for functioning as an defoaming agent in water-based paints, and by stabilizing their dispersion.

[0033] In this invention, HLB is determined by the following formula based on the Griffin method. HLB = 20 × sum of formula weights of hydrophilic parts / molecular weight

[0034] The definition of the hydrophilic part in the above equation is as described above.

[0035] <Specific example> The nonionic surfactant (A) according to the present invention is selected to be a nonionic surfactant having the hydrophilic portion described above and having an HLB value within the range described above, and being in a liquid state in the liquid medium contained in the composition at 25°C and not existing in a solid state (i.e., not existing as fine particles in the defoaming agent composition). An example of a method for determining whether a compound containing the above-described hydrophilic portion and having an HLB value within the range described above, contained in the defoaming agent composition according to the present invention, corresponds to the nonionic surfactant (A) according to the present invention is as follows. For example, after dispersing the compound to be identified in a mixture of liquid medium components excluding the compound to be identified contained in the defoaming agent composition in a range in which the content of the compound to be identified does not exceed 50% by mass, the dispersion is filtered, and then the mixture is thoroughly washed. If no filtration residue is obtained, the compound to be identified can be determined to be a nonionic surfactant (A). On the other hand, if filtration residue is obtained after the above filtration and washing, the compound to be identified can be determined to be a nonionic surfactant (A) by performing a qualitative analysis to confirm that the compound to be identified is not contained.

[0036] As the nonionic surfactant (A), one or more of the following can be used: ethylene glycol aliphatic ether, polyoxyalkylene aliphatic ether, polyoxyalkylene aromatic ether, polyoxyalkylene fatty acid ester, alkylene oxide adsorption derivative of castor oil, alkylene oxide adsorption derivative of hydrogenated castor oil, polyoxyalkylene polyhydric alcohol ether, polyhydric alcohol fatty acid ester, alkylene oxide adsorption derivative of polyhydric alcohol fatty acid ester, polyoxyalkylene alkylamide, acetylene glycol and its derivatives, alkylene oxide adsorption derivative of acetylene glycol, polyoxyethylene-polyoxypropylene block copolymer, and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer.

[0037] As an ethylene glycol aliphatic ether, for example, one in which an aliphatic chain with 9 to 22 carbon atoms is etherically linked to ethylene glycol can be used.

[0038] As polyoxyalkylene aliphatic ethers, for example, those with 1 to 22 carbon atoms from among polyoxyethylene aliphatic ethers and polyoxyethylene-polyoxypropylene aliphatic ethers can be used. As polyoxyalkylene aromatic ethers, for example, those with 6 to 28 carbon atoms from among polyoxyethylene aromatic ethers and polyoxyethylene-polyoxypropylene aromatic ethers can be used. As polyoxyalkylene fatty acid esters, for example, those with 1 to 22 carbon atoms from among polyoxyethylene fatty acid esters and polyoxyethylene-polyoxypropylene fatty acid esters can be used.

[0039] Examples of alkylene oxide addition derivatives of castor oil or hydrogenated castor oil include polyoxyalkylene castor oil ethers such as polyoxyethylene castor oil ether and polyoxyethylene-polyoxypropylene castor oil ether; polyoxyalkylene hydrogenated castor oil ethers such as polyoxyethylene hydrogenated castor oil ether and polyoxyethylene-polyoxypropylene hydrogenated castor oil ether; polyoxyalkylene castor oil ether fatty acid esters such as polyoxyethylene castor oil ether fatty acid esters and polyoxyethylene-polyoxypropylene castor oil ether fatty acid esters; polyoxyethylene hydrogenated castor oil ether fatty acid esters (e.g., polyoxyethylene hydrogenated castor oil monoisostearate, polyoxyethylene hydrogenated castor oil triisostearate, etc.); and polyoxyalkylene hydrogenated castor oil ether fatty acid esters such as polyoxyethylene-polyoxypropylene hydrogenated castor oil ether fatty acid esters.

[0040] Here, for example, when using an ethylene oxide adduct of castor oil or hydrogenated castor oil, the number of moles of ethylene oxide (EO) added to the castor oil or hydrogenated castor oil is preferably 5 moles to 100 moles, and more preferably 5 moles to 60 moles. By setting the number of moles of EO added within the above range, the defoaming properties and shear resistance of the defoaming agent of the present invention can be improved.

[0041] As polyoxyalkylene polyhydric alcohol ethers, for example, polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, monosaccharides, disaccharides, trisaccharides, oligosaccharides, polysaccharides, sorbitol, and sorbitan, to which alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide can be added. As polyhydric alcohol fatty acid esters, for example, esters of polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, monosaccharides, disaccharides, trisaccharides, oligosaccharides, polysaccharides, sorbitol, and sorbitan having glucose or fructose skeletons, and fatty acids such as acetic acid, propionic acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, 12-hydroxystearic acid, linoleic acid, linolenic acid, behenic acid, and erucic acid can be used. As polyhydric alcohol fatty acid ester alkylene oxide addition derivatives, for example, those obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to the above polyhydric alcohol fatty acid esters can be used. As polyoxyalkylene alkylamides, for example, polyoxyethylene stearylamide and polyoxyethylene oleylamide can be used.

[0042] Commercially available products can be used as acetylene glycol and its derivatives, as well as alkylene oxide addition derivatives of acetylene glycol. Examples include the Surfinol (registered trademark: product name of Nisshin Chemical Industry Co., Ltd.) series and the Acetylenel (registered trademark: product name of Kawaken Fine Chemical Co., Ltd.) series.

[0043] Furthermore, the number of moles of ethylene oxide (EO) added to acetylene glycol or an acetylene glycol derivative is preferably 1 mole to 10 moles. Here, from the viewpoint of enhancing the defoaming properties of the defoaming agent of the present invention, it is more preferable that the number of moles of EO added is 1 mole to 4 moles.

[0044] As the polyoxyethylene-polyoxypropylene block copolymer, or polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, for example, one can be used in which the total mass of ethylene oxide blocks within the copolymer molecule is 10% to 50% by mass, more preferably 10% to 20% by mass, and the weight-average molecular weight of the propylene oxide blocks is 700 to 4000, more preferably 3000 to 4000. Within the above range, it is even more desirable that the block copolymer be of a liquid type.

[0045] Of the specific examples shown above, it is preferable to use polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil triisostearate, etc., in order to enhance the defoaming properties.

[0046] <Content> The content of the nonionic surfactant (A) described above is preferably 5% to 80% by mass, when the total mass of all components in the defoaming agent composition is taken as 100% by mass. By setting the content of nonionic surfactant (A) to 5% to 80% by mass, sufficient defoaming properties can be achieved. To further enhance the defoaming effect, it is even more preferable to set the content of nonionic surfactant (A) to 10% to 50% by mass.

[0047] (Polymer (B)) The polymer (B) according to the present invention is a component for exhibiting defoaming properties and is a component added to enhance the permeability of the defoaming agent into the foam film. As this polymer (B), a polymer having an SP value of 7.5 to 12 and a weight average molecular weight of 400 to 1,000,000 is used. Further, as the polymer (B), those having no hydrophilic part (ethylene glycol part, polyethylene glycol part, polyhydric alcohol part) described above in the molecule and having a liquid or rubbery form, or those which are solid at 25°C but are in a liquid state in the liquid medium contained in the composition at 25°C and do not exist in the solid state (that is, those which do not exist as fine particles in the defoaming agent composition) are selected. The liquid ones can be used alone, and the rubbery and solid ones are used after being dissolved in a liquid component.

[0048] <SP value · weight average molecular weight> The SP value of the polymer (B) according to the present invention is in the range of 7.5 to 12. If the SP value is less than 7.5, there is a risk of causing defects in the coating appearance such as repellency and bumps. On the other hand, if the SP value exceeds 12, the defoaming effect is poor, and there is a risk that satisfactory defoaming properties cannot be obtained. Further, in order to further enhance the defoaming property, the SP value is preferably 7.5 to 11, more preferably 8.0 to 9.5, and even more preferably 8.0 to 9.0.

[0049] As the SP value in the present invention, the value calculated by Fedors' method is used, and the unit is (cal / cm 3 ) 1 / 2 . Fedors' method is a method of estimating the SP value from the molecular structure, and the SP value can be estimated from the relationship between the cohesive energy (cal / mol) per atomic group and the molar molecular volume (cm 3 / mol).

[0050] Furthermore, the weight-average molecular weight of polymer (B) according to the present invention is in the range of 400 to 1,000,000. If the weight-average molecular weight is less than 400, sufficient defoaming properties cannot be achieved. On the other hand, if the weight-average molecular weight exceeds 1,000,000, it becomes difficult to uniformly disperse polymer (B) in the paint, leading to problems such as paint repellency and dents. In addition, to further enhance defoaming properties, a weight-average molecular weight of 400 to 300,000 is preferable.

[0051] In this invention, the weight-average molecular weight is a value calculated from a chromatogram measured by gel permeation chromatography (GPC), based on the molecular weight of standard polystyrene.

[0052] <Specific example> The polymer (B) according to the present invention is a polymer having the above-mentioned SP value and weight-average molecular weight, and not having an ethylene glycol portion, a polyethylene glycol portion, or a polyhydric alcohol portion. Here, "polymer (B)" in the present invention is a compound with a degree of polymerization of 3 or more, using monomer units as repeating units, or a derivative thereof. As polymer (B), one or more polymers from among polyvinyl alkyl ether, polybutadiene, polybutene, polyisoprene, polyalphaolefin, polyalkyl (meth)acrylate, copolymer of dibasic acid ester, polyfatty acid vinyl ester, copolymer of alkyl (meth)acrylate and fatty acid vinyl ester, and polyalkylene glycol derivative (however, the polyalkylene glycol derivative does not have the above-mentioned ethylene glycol portion, polyethylene glycol portion, and polyhydric alcohol portion, and the weight-average molecular weight of the polyalkylene glycol derivative is 400 to 1,000,000) can be suitably used.

[0053] The above polyvinyl alkyl ether is obtained by polymerizing a vinyl ether monomer having an alkyl group with 1 to 18 carbon atoms. Examples of vinyl ether monomers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, isononyl vinyl ether, dodecyl vinyl ether, tetradecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether, etc., and one or more monomers from these can be arbitrarily selected and used.

[0054] Polyvinyl alkyl ethers are obtained by polymerizing the above monomers by cationic polymerization. The weight-average molecular weight of the polyvinyl alkyl ether is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. If the weight-average molecular weight is less than 1,000, it may not be able to exhibit sufficient defoaming performance. If the weight-average molecular weight exceeds 500,000, it becomes difficult to uniformly disperse it in the paint, which may cause problems such as repelling and denting.

[0055] As polybutadiene, homopolymers and copolymers of 1,3-butadiene (CH2=CH-CH=CH2) or 1,2-butadiene (CH2=C=CH-CH3) can be used. Commercially available polybutadiene may also be used. Commercially available polybutadienes include homopolymers, hydrogenated types, terminal carboxylic acid group types, terminal hydroxyl group types, etc. Examples of homopolymers include B-1000 (15-25-mers: number average molecular weight approximately 1000), B-2000 (30-40-mers: number average molecular weight approximately 2000), and B-3000 (45-65-mers: number average molecular weight approximately 3000) (all manufactured by Nippon Soda Co., Ltd.). Examples of hydrogenated types include BI-2000 (30-40 mers: number average molecular weight approximately 2000) and BI-3000 (45-65 mers: number average molecular weight approximately 3000) (both manufactured by Nippon Soda Co., Ltd.). Examples of terminal carboxylic acid group types include C-1000 (20-30 mers: number average molecular weight approximately 1400) (manufactured by Nippon Soda Co., Ltd.). Examples of terminal hydroxyl group types include G-1000 (20-30 mers: number average molecular weight approximately 1500), G-2000 (30-40 mers: number average molecular weight approximately 2000), G-3000 (45-60 mers: number average molecular weight approximately 2900) (all manufactured by Nippon Soda Co., Ltd.), Poly bd R-15HT (20-25 mers: number average molecular weight approximately 1200), Poly bd R-45HT (45-55 mers: number average molecular weight approximately 2800) (all manufactured by Idemitsu Kosan Co., Ltd.). One or more of these polymers can be arbitrarily selected and used.

[0056] The weight-average molecular weight of polybutadiene is preferably 2,000 to 300,000, more preferably 2,000 to 230,000, even more preferably 2,000 to 200,000, and most preferably 3,000 to 10,000. If the weight-average molecular weight is less than 2,000, it may not exhibit sufficient defoaming performance. If the weight-average molecular weight exceeds 300,000, it becomes difficult to uniformly disperse it in the paint, which may cause problems such as repelling, denting, and loss of gloss in the paint film. Furthermore, the SP value of polybutadiene is more preferably 7.5 to 9.0.

[0057] Polybutenes that can be used include 1-butene homopolymers and copolymers of 1-butene and isobutene. Commercially available polybutenes may also be used. Commercially available polybutenes include copolymers of 1-butene and isobutene, 1-butene homopolymers, and hydrogenated polybutenes. Examples of copolymers of 1-butene and isobutene include LV-7 (4-6 mers: number average molecular weight approximately 300), LV-50 (6-9 mers: number average molecular weight approximately 450), LV-100 (8-12 mers: number average molecular weight approximately 500), HV-15 (9-13 mers: number average molecular weight approximately 630), HV-35 (10-15 mers: number average molecular weight approximately 750), HV-50 (12-16 mers: number average molecular weight approximately 800), HV-100 (16-20 mers: number average molecular weight approximately 980), HV-300 (23-27 mers: number average molecular weight approximately 1400), and HV-1900 (45-55 mers: number average molecular weight approximately 2900) (all manufactured by ENEOS Corporation). Examples of 1-butene homopolymers include 15R (9-11 mers: number average molecular weight approximately 570), 35R (12-14 mers: number average molecular weight approximately 720), 100R (16-20 mers: number average molecular weight approximately 960), and 300R (24-30 mers: number average molecular weight approximately 1500) (all manufactured by Idemitsu Kosan Co., Ltd.). Examples of hydrogenated types include 0H (5-7 mers: number average molecular weight approximately 350), 5H (6-8 mers: number average molecular weight approximately 400), 10H-T (7-10 mers: number average molecular weight approximately 470), 300H (24-30 mers: number average molecular weight approximately 1500), and 2000H (50-55 mers: number average molecular weight approximately 3000) (all manufactured by Idemitsu Kosan Co., Ltd.). One or more of these polymers can be arbitrarily selected and used.

[0058] The weight-average molecular weight of polybutene is preferably 400 to 50,000, and more preferably 400 to 20,000. If the weight-average molecular weight is less than 400, it may not exhibit sufficient defoaming performance. If the weight-average molecular weight exceeds 50,000, it becomes difficult to uniformly disperse it in the paint, which may cause problems such as repelling, denting, and loss of gloss in the paint film. Furthermore, the SP value of polybutene is more preferably 7.5 to 9.0.

[0059] Commercially available polyisoprene can be used. Commercially available polyisoprene includes terminal hydroxyl group type and hydrogenated type. Examples of terminal hydroxyl group type include Poly iP (30-40-mer: number average molecular weight approximately 2500) (manufactured by Idemitsu Kosan Co., Ltd.). Examples of hydrogenated type include Epol (manufactured by Idemitsu Kosan Co., Ltd.), which is a hydrogenated form of Poly iP. One or more of these polymers can be arbitrarily selected and used.

[0060] The weight-average molecular weight of polyisoprene is preferably 2,000 to 50,000, and more preferably 3,000 to 20,000. If the weight-average molecular weight is less than 2,000, it may not exhibit sufficient defoaming performance. If the weight-average molecular weight exceeds 50,000, it becomes difficult to uniformly disperse it in the paint, which may cause problems such as repelling, denting, and loss of gloss in the paint film. Furthermore, the SP value of polyisoprene is more preferably 7.5 to 9.0.

[0061] Examples of polyalphaolefins include poly(1-hexene), poly(1-octene), poly(1-decene), poly(1-dodecene), and ethylene-propylene copolymer, and one or more of these can be arbitrarily selected and used.

[0062] The weight-average molecular weight of the polyalphaolefin is preferably 400 to 100,000, more preferably 400 to 10,000, and even more preferably 500 to 5,000. If the weight-average molecular weight is less than 400, it may not be able to exhibit sufficient defoaming performance. If the weight-average molecular weight exceeds 100,000, it becomes difficult to uniformly disperse it in the paint, which may cause problems such as repelling, denting, and loss of gloss of the paint film. Furthermore, the SP value of the polyalphaolefin is more preferably 7.5 to 9.0.

[0063] Furthermore, in addition to the polymers described above, polymers such as polyalkyl (meth)acrylate, dibasic acid ester copolymers, polyfatty acid vinyl esters, alkyl (meth)acrylate and fatty acid vinyl ester copolymers, and polyalkylene glycol derivatives (which do not have an ethylene glycol portion, a polyethylene glycol portion, or the above-mentioned polyhydric alcohol portion, and have a weight-average molecular weight of 400 to 1,000,000) may be used as polymer (B) according to the present invention. Examples of polyalkyl (meth)acrylates include polymers or copolymers of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, oleyl (meth)acrylate, behenyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, isobolonyl (meth)acrylate, etc. Examples of dibasic acid ester copolymers include polymers or copolymers of maleic acid monoesters or diesters, and fumaric acid monoesters or diesters. Examples of polyfatty acid vinyl esters include polymers or copolymers of vinyl acetate, vinyl pivalate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl palmitate, vinyl octoate, vinyl 2,2-dimethyloctanoate, vinyl neononanoate, vinyl neodecanoate, and vinyl neoundecanoate. Examples of alkyl (meth)acrylate and fatty acid vinyl ester copolymers include copolymers consisting of the above (meth)acrylate and the above fatty acid vinyl.With regard to copolymers of polyalkyl (meth)acrylates, dibasic acid esters, polyfatty acid vinyl esters, and copolymers of alkyl (meth)acrylates and fatty acid vinyl esters, monomers other than those mentioned above, which do not contain the ethylene glycol portion, polyethylene glycol portion, or polyhydric alcohol portion, may be copolymerized in a range not exceeding 50 mol%, provided that the defoaming properties and shear resistance are not impaired. Examples of polyalkylene glycol derivatives include polypropylene glycol, polybutylene glycol, polypropylene glycol monobutyl ether, polypropylene glycol monostearyl ether, and polypropylene glycol and polybutylene glycol adducts added to polyhydric alcohols such as glycerin, trimethylolpropane, and sugars, and which do not fall under the category of nonionic surfactant (A).

[0064] Of the specific examples shown above, it is preferable to use polyvinyl alkyl ether, polybutadiene, polybutene, polyalphaolefin, etc., in order to improve defoaming properties, paint appearance, shear resistance, and topcoatability.

[0065] <Content> The content of polymer (B) described above is preferably 10% to 90% by mass, when the total mass of all components in the defoaming agent composition is taken as 100% by mass. By setting the content of polymer (B) to 10% to 90% by mass, sufficient defoaming performance can be achieved. To further enhance the defoaming effect, it is even more preferable to set the content of polymer (B) to 20% to 70% by mass.

[0066] (Organic solid particles (C)) The organic solid fine particles (C) according to the present invention are components that exhibit defoaming properties and are added to enhance the defoaming effect of the defoaming agent and to improve the shear resistance of the paint. The organic solid fine particles (C) are selected from materials having a melting point of at least 50°C and are solid fine particles at 25°C. Such organic solid fine particles (C) are in a solid state in the liquid medium contained in the composition at 25°C. Furthermore, the organic solid fine particles (C) are fine particles with a particle size of 0.1 μm or more when present in the defoaming agent composition and are selected to not dissolve or change the shape of their primary particles in the defoaming agent composition at 25°C.

[0067] Here, "primary particles" in this invention refers to isolated particles that cannot be further divided into smaller particles even when diluted with a predetermined medium. Furthermore, a known qualitative method can be used to determine whether organic solid fine particles (C) are in a solid state in the liquid medium contained in the defoaming agent composition at 25°C. For example, one method involves dispersing the organic solid fine particles in the liquid medium contained in the composition in an amount not exceeding 50% by mass, separating the non-flowing components from the dispersion by filtration or centrifugation, and then measuring their melting points.

[0068] <Particle shape> The organic solid fine particles (C) are solid fine particles made of organic compounds, and are selected to not disperse in water on their own. Furthermore, when their particle size distribution is measured by laser diffraction / scattering measurement, etc., their particle size has a peak in the range of 0.1 to 150 μm. That is, the peak particle size (also called "mode diameter") of the organic solid fine particles (C) is preferably in the range of 0.1 to 150 μm, more preferably 2 to 150 μm, and even more preferably 2 to 50 μm. By having the peak particle size of the organic solid fine particles (C) within the above range, an antifoaming agent composition with particularly excellent shear resistance can be obtained.

[0069] Regarding particle shape, particles with uneven surfaces are preferable to perfectly spherical particles, and porous particles or particles with thorn-like protrusions are even more desirable. Such particles may be clusters of fine particles, for example, in which the aspect ratio of the primary particles is 1.1 to 100. In particular, when the above clusters are used, a mixed liquid consisting of an antifoaming liquid component (e.g., a nonionic surfactant (A) or polymer (B)) and an organic medium (D) can be suitably held on the surface of the fine particles, resulting in particularly excellent shear resistance. The aspect ratio of the primary particles can be controlled by appropriately adjusting the temperature and the time for holding the temperature when precipitating and growing the fine particles during the process of producing organic solid fine particles (C).

[0070] When the aspect ratio is less than 1.1, it is difficult to form clusters, making it difficult to retain the defoaming liquid component, and thus it is difficult to obtain excellent shear resistance. On the other hand, when the aspect ratio exceeds 100, the voids in the clusters become too large, making it difficult to retain the defoaming liquid component, and in this case as well, it is difficult to obtain excellent shear resistance. From the viewpoint of further improving shear resistance, the more preferable range for the aspect ratio is 1.5 to 50, the even more preferable range is 2.0 to 11, and the most preferable range is 2.0 to 9.0.

[0071] The aspect ratio of the primary microparticles described above can be calculated by measuring the shape of isolated microparticles during TEM or SEM observation. Specifically, it can be calculated using the following method, for example: Dilute and suspend the microparticles to be measured in a suitable volatile organic solvent in which the microparticles do not dissolve, then drop them onto a TEM observation grid or SEM observation sample mount and dry them to prepare an observation sample. At this time, adjust the solvent type and dilution amount as appropriate so that the microparticles are isolated. Set the magnification of the prepared sample using TEM or SEM to a level that makes it easy to observe isolated microparticles, and confirm the shape of the isolated microparticles. If the shape of the microparticles can be considered elliptical, measure the distance between the minor axis and the major axis, and calculate the major axis / minor axis value. Perform the same measurement for at least 10 microparticles, and take the average as the aspect ratio of that microparticle. If the microparticles are fibrous and it is difficult to consider them elliptical, take the median of the measured fiber widths as the fiber width, and calculate the fiber length / fiber width value. Perform the same measurements on at least 10 isolated fibrous microparticles, and use the average of these measurements as the aspect ratio of the fibrous microparticle.

[0072] <Specific example> The organic solid particles (C) are not particularly limited, but for example, one or more solid particles from amides, ureas, polyethylene, oxidized polyethylene, acid-modified polyethylene, and hydrogenated castor oil can be suitably used.

[0073] Amides can be obtained, for example, by condensation reactions of fatty acids and amines. The conditions for the condensation reaction (reaction temperature, mixing ratio of each component, etc.) can be appropriately set by known methods. For example, fatty acids and amines, which are the raw materials, are placed in a reaction vessel such as a four-necked flask, and the raw materials are stirred in an inert gas atmosphere (for example, under a nitrogen gas stream) to form a mixture. Then, the mixture of raw materials is heated and polycondensed at 150°C to 200°C for 2 to 10 hours to synthesize fatty acid amides. Monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids can be used as fatty acids, and monoamines, diamines, and triamines can be used as amines.

[0074] Examples of monocarboxylic acids that can be used include saturated aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated castor oil fatty acids (12-hydroxystearic acid (hereinafter referred to as "12-HSA") obtained by saponification of hydrogenated castor oil, and other hydroxyl-containing fatty acids), arachidic acid, behenic acid (behenic acid), and unsaturated aliphatic monocarboxylic acids such as oleic acid, linoleic acid, ricinoleic acid, linolenic acid, eicosenoic acid, erucic acid (erucic acid), and mixed fatty acids obtained from natural oils and fats (tall oil fatty acids, rice bran fatty acids, soybean oil fatty acids, beef tallow fatty acids, etc.). Among these monocarboxylic acids, it is preferable that the monocarboxylic acid contains at least a hydroxy fatty acid such as 12-HSA in order to improve the defoaming and shear resistance of water-based paints. In other words, as the amide used as the organic solid fine particles (C) of the present invention, an amide in which at least one of the fatty acids is a hydroxy fatty acid is preferred.

[0075] Dicarboxylic acids can be used, for example, dicarboxylic acids having 4 to 44 carbon atoms. Examples of such dicarboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanediic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and dimer acid. Dimer acid is a polymerized fatty acid obtained by polymerizing (dimerizing) unsaturated fatty acids (for example, unsaturated fatty acids with 18 or 22 carbon atoms) obtained from vegetable oils such as soybean oil, tall oil, linseed oil, and cottonseed oil. Generally, dimer acid with 36 or 44 carbon atoms is commercially available.

[0076] Tricarboxylic acids can be used, for example, tricarboxylic acids having 4 to 54 carbon atoms. Examples of such tricarboxylic acids include trimer acid and trimesic acid. Trimer acid is a polymerized fatty acid based on dimer acid, with a high trimer acid content achieved through distillation purification or other methods. Generally, trimer acid with 54 carbon atoms is commercially available.

[0077] Examples of monoamines include ethylamine, monoethanolamine, propylamine, butylamine, pentylamine, hexylamine, octylamine, decylamine, laurylamine, myristylamine, cetylamine, stearylamine, 12-hydroxystearylamine, and behenylamine.

[0078] Examples of diamines that can be used include aliphatic diamines such as 1,2-diaminoethane (ethylenediamine: EDA), 1,2-diaminopropane (propylenediamine: PDA), 1,4-diaminobutane (tetramethylenediamine: TMDA), 1,6-diaminohexane (hexamethylenediamine: HMDA), 1,8-diaminooctane (octamethylenediamine: OMDA), trimethylhexamethylenediamine, and 1,12-diaminododecane (dodecamethylenediamine: DMDA); aromatic diamines such as o-xylylenediamine, m-xylylenediamine (MXDA), p-xylylenediamine (PXDA), diaminodiphenylmethane, diaminodiphenyl ether, diaminodiphenyl sulfone, and methylenebischloroaniline; and alicyclic diamines such as piperazine, isophoronediamine, and 1,3-bisaminomethylcyclohexane, which have 2 to 54 carbon atoms.

[0079] As the triamine, triamines with 2 to 54 carbon atoms, such as aliphatic triamines like diethylenetriamine, can be used.

[0080] Furthermore, when synthesizing the amides of the present invention, diamines or triamines derived from polymerized fatty acids, which are polymerized fatty acid derivatives, can also be used as amines. Examples of such polymerized fatty acid derivatives include dimer amine (DDA), a dimer acid derivative, and trimer triamine (TTA), a trimer acid derivative. Dimer amines, as dimer acid derivatives, are those in which the two terminal carboxyl groups of the aforementioned dimer acid are replaced with primary aminomethyl groups or amino groups, and commercially available products can be used. Similarly, trimer triamines, as trimer acid derivatives, are those in which the three terminal carboxyl groups of the aforementioned trimer acid are replaced with primary aminomethyl groups or amino groups, and commercially available products can be used.

[0081] The compounds used as fatty acids and amines mentioned above can be selected individually or in groups of two or more.

[0082] Here, from the viewpoint of further enhancing shear resistance, it is preferable that the amide is a diamide. Diamides can be obtained by reacting a fatty acid with a diamine, or by reacting a monoamine with a dicarboxylic acid. Among diamides, it is even more preferable that the diamide is a fatty acid diamide obtained by reacting the following fatty acids with the following diamines. The fatty acids used in the synthesis of the fatty acid diamide are selected from the group consisting of alkyl fatty acids (saturated fatty acids) and hydroxy fatty acids, and include at least one hydroxy fatty acid. The diamines used in the synthesis of the above fatty acid diamide include one or more diamines selected from the group consisting of alkylenediamines having 2 to 6 carbon atoms and m-xylylenediamine. Among these fatty acid diamides, using ethylenebis-12-hydroxystearate diamide, 1,4-butanebis-12-hydroxystearate diamide, hexamethylenebis-12-hydroxystearate diamide, etc. as organic solid fine particles (C) can provide particularly excellent shear resistance to the water-based paint containing the defoaming agent of the present invention.

[0083] Urea is a polymer, oligomer, diurea, or monourea having a urea bond, obtained by the reaction of an isocyanate compound and an amine compound. One or more compounds from the following lists can be arbitrarily selected as the isocyanate compound and amine compound.

[0084] Examples of isocyanate compounds that can be used include aromatic monoisocyanates, aliphatic monoisocyanates, alicyclic monoisocyanates, compounds obtained by making these monoisocyanates non-volatile and reducing their toxicity, aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, compounds obtained by making these diisocyanates non-volatile and reducing their toxicity, adduct forms such as biuret, uretdione, isocyanurate, and allohanate forms of these diisocyanates, and relatively low molecular weight urethane prepolymers. Examples of aromatic diisocyanates include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), and m-xylylene diisocyanate (MXDI). Examples of aliphatic diisocyanates include hexamethylene diisocyanate (HDI). Examples of alicyclic diisocyanates include isophorone diisocyanate (IPDI) and hydrogenated MDI. Commercially available polyisocyanates may also be used. Examples of commercially available products include Aquanate 130, Aquanate 140, Aquanate 200 and Aquanate 210 (manufactured by Tosoh Corporation), Bahijur 304, Bahijur XP-2655, Bahijur 401-70, Bahijur 3100 (manufactured by Sumika Covestro Urethane Co., Ltd.), Barnock DNW-5000, Barnock DNW-5500, Barnock DNW-6000 (manufactured by DIC Corporation), Rezamin D-1063, Rezamin D-2040 (manufactured by Dainichi Seika Kogyo Co., Ltd.).

[0085] Amine compounds include monoamines and polyamines.

[0086] Examples of monoamines that can be used include aliphatic monoamines, alicyclic monoamines, aromatic monoamines, and alkanolamines. Examples of aliphatic monoamines include alkyl monoamines and other aliphatic monoamines. Examples of alkyl monoamines include octylamine, dodecylamine, octadecylamine, and octadecenylamine. Examples of alicyclic monoamines include cyclohexylamine. Examples of aromatic monoamines include aniline and toluidine. Examples of alkanolamines that can be used include ethanolamine, 2-amino-2-methyl-1-propanol, and 12-hydroxystearylamine.

[0087] Examples of polyamines that can be used include aliphatic polyamines, alicyclic polyamines, and aromatic polyamines. Examples of aliphatic polyamines include alkylene polyamines, polyalkylene polyamines, and other aliphatic polyamines. Examples of alkylene polyamines include diaminomethane (methylenediamine), 1,2-diaminoethane, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane. Examples of polyalkylene polyamines include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexamethylenetetramine. Other aliphatic polyamines include, for example, tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, bishexamethylenetriamine, and polyethyleneimine. Alicyclic polyamines include, for example, 1,4-cyclohexanediamine, 4,4'-methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornadiamine, bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane, isophoronediamine, and mensendiamine (MDA).Examples of aromatic polyamines include bis(cyanoethyl)diethylenetriamine, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, phenylenediamine, naphthylenediamine, diaminodiphenylmethane, diaminodiethylphenylmethane, 2,2-bis(4-aminophenyl)propane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 2,4'-diaminobiphenyl, 2,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, bis(aminomethyl)naphthalene, and bis(aminoethyl)naphthalene.

[0088] Oxidized polyethylene is a wax obtained by oxidizing polyethylene and introducing polar groups. Acid-modified polyethylene is obtained by grafting polyethylene with an unsaturated carboxylic acid or its anhydride.

[0089] Hydrogenated castor oil (also called "hardened castor oil") is a saturated fatty acid triglyceride obtained by hydrogenating castor oil. Commercially available hydrogenated castor oils can be used, and examples of commercially available products include C-wax (manufactured by Ogura Synthetic Industry Co., Ltd.), Kao Wax 85P (manufactured by Kao Corporation), Castor Hydrogenated Oil A (manufactured by Ito Oil Co., Ltd.), and Castor Hydrogenated Oil (manufactured by Yamakei Sangyo Co., Ltd.).

[0090] Furthermore, in addition to the examples described above, other organic solid fine particles (C) according to the present invention may be used, such as a copolymer of polyalkyl (meth)acrylate, a dibasic acid ester, or a copolymer of alkyl (meth)acrylate and fatty acid vinyl ester (provided that it is in a solid state in the defoaming agent composition at 25°C (i.e., does not belong to the nonionic surfactant (A) and polymer (B))).

[0091] Among the specific examples shown above, it is preferable to use ethylenebis-12-hydroxystearate diamide, 1,4-butanebis-12-hydroxystearate diamide, hexamethylenebis-12-hydroxystearate diamide, etc., in order to improve defoaming properties and shear resistance.

[0092] <Content> The content of the organic solid particles (C) described above is preferably 0.1% to 10% by mass, when the total mass of all components in the defoaming agent composition is taken as 100% by mass. By setting the content of organic solid particles (C) to 0.1% to 10% by mass, sufficient defoaming properties and shear resistance can be achieved. To further improve the appearance of the coating film obtained with the water-based coating composition to which the defoaming agent composition has been added, it is even more preferable to set the content of organic solid particles (C) to 1% to 5% by mass.

[0093] (Organic medium (D)) The organic medium (D) according to the present invention is a component that exhibits antifoaming properties together with the nonionic surfactant (A) and polymer (B) described above, and is a component added to enhance the diffusivity of the antifoaming agent in the foam film.

[0094] <Liquidity> As the organic medium (D), any medium other than water that does not have the aforementioned hydrophilic portion in its molecule and is liquid at 25°C can be used. Furthermore, as the organic medium (D), a weight-average molecular weight of less than 400 is selected. By using such a medium, the diffusivity of the defoaming agent according to the present invention in the foam film can be improved.

[0095] <Specific example> As the organic medium (D), one or more selected from the group consisting of hydrocarbon oils, alcohols, glycol ethers, and glycol esters (those not included in nonionic surfactants (A) and polymers (B)) can be suitably used.

[0096] Examples of hydrocarbon oils include those with the general formula C n H 2n+2n-paraffins and isoparaffins represented by, and cycloalkanes represented by C n H 2n One or more selected from can be used.

[0097] As an example of the n-paraffin represented by the general formula C n H 2n+2 Examples of n-paraffins represented by include n-hexane, n-heptane, n-octane, n-decane, n-dodecane, liquid paraffin, etc. Furthermore, generally commercially available n-paraffin-based mixed solvents can also be used. Commercially available products of n-paraffin-based mixed solvents include, for example, Solvent L No. 0 (ENEOS Corporation), etc. One or more of these can be arbitrarily selected and used.

[0098] As an example of the isoparaffin represented by the general formula C n H 2n+2 Examples of isoparaffins represented by include isohexane, isooctane, isododecane, isohexadecane, etc. Furthermore, generally commercially available isoparaffin-based mixed solvents can also be used. Commercially available products of isoparaffin-based mixed solvents include, for example, IP Solvent, Melbayu 30 (both manufactured by Idemitsu Kosan Co., Ltd.), Shellsol T series (manufactured by Shell Chemicals), IsoPar series (manufactured by ExxonMobil Corporation), etc. One or more of these can be arbitrarily selected and used.

[0099] As an example of the cycloalkane represented by the general formula C n H 2n Commercially available naphthene-based solvents, etc. can be used. Commercially available products of naphthene-based solvents include, for example, methylcyclohexane, ethylcyclohexane, Swaclean 150 (alias: mixture of C9 and C10 alkylcyclohexanes) (both manufactured by Maruzen Petrochemical Co., Ltd.), Naftazol series, Cactus Solvent series (both manufactured by ENEOS Corporation), etc. One or more of these can be arbitrarily selected and used.

[0100] Also, as the organic medium (D), the general formula C used in the present inventionn H 2n+2 n-paraffins and isoparaffins represented by C n H 2n You may use a solvent that is commercially available with at least two of the cycloparaffins represented by the formula already mixed. Examples of such solvents include Naphthezol M (naphthene / isoparaffin / n-paraffin = 70% or more / 5-10% / 15% or less, a product name of ENEOS Corporation), Isosol 300 (a product name of ENEOS Corporation), Isosol 400 (a product name of ENEOS Corporation), Exsol D80 (a mixed solvent of paraffin and cycloparaffin, a product name of ExxonMobil Corporation), Exsol D110 (a mixed solvent of paraffin and cycloparaffin, a product name of ExxonMobil Corporation), Exsol D130 (a mixed solvent of paraffin and cycloparaffin, a product name of ExxonMobil Corporation), Exsol D160 (a mixed solvent of paraffin and cycloparaffin, a product name of ExxonMobil Corporation), etc. You may arbitrarily select and use one or more of these.

[0101] Examples of alcohols that can be used include ethanol, n-propanol, IPA, n-butanol, sec-butanol, tert-butanol, 2-ethylhexanol, isostearyl alcohol, oleyl alcohol, and texanol. Examples of glycol ethers that can be used include butyl glycol, 2-ethylhexyl glycol, methyl diglycol, dimethyl diglycol, methyl triglycol (HLB:18), methylpropylene glycol, n-propylpropylene glycol, butylpropylene glycol, methyl dipropylene glycol, propyl dipropylene glycol, and butyl dipropylene glycol. Examples of glycol esters that can be used include propylene glycol monomethyl ether acetate and dipropylene glycol monomethyl ether acetate.

[0102] Furthermore, in addition to those mentioned above, other organic media (D) may be used, such as aromatic solvents like xylene and toluene; ketone solvents like methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), and methyl amyl ketone (MAK: also called 2-heptanone); ether solvents like cyclopentyl methyl ether; ester solvents like acetate esters and ethyl 3-ethoxypropionate; amide solvents like dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide; polyethers; oils and fats; and polyalkylene glycol derivatives (those not included in nonionic surfactants (A) and polymers (B)).

[0103] <Content> The content of the organic medium (D) described above is preferably 0.5% to 70% by mass, when the total mass of all components in the defoaming agent composition is taken as 100% by mass. By setting the content of the organic medium (D) to 0.5% to 70% by mass, sufficient defoaming performance can be achieved. To further enhance the defoaming effect, it is even more preferable to set the content of the organic medium (D) to 5% to 50% by mass.

[0104] (Other optional components) The defoaming agent composition of the present invention may contain other components besides those listed above, and other than silicone compounds, to the extent that they do not impair the characteristics of the present invention, in order to impart other functions. For example, solvents, surfactants, amphiphilic compounds, or paint additives other than defoaming agents may be added for the purpose of uniformly dissolving or dispersing the above-mentioned components (A) to (D), or improving the leveling properties and uniformity of paints to which the defoaming agent has been added. Specifically, examples include water, nonionic surfactants, ionic surfactants, leveling agents, dispersants, etc. (however, those not included in the above-mentioned nonionic surfactant (A), polymer (B), organic solid fine particles (C), and organic medium (D)).

[0105] (Components not included in the antifoaming agent composition according to the present invention) The defoaming agent composition according to the present invention preferably does not contain silicone compounds (synthetic polymers having a main skeleton of siloxane bonds). If silicone compounds are included in the defoaming agent composition according to the present invention, the bleeding of the silicone component onto the coating surface may cause paint repellency or inhibit the ability to apply topcoats. Thus, if silicone compounds are included in the defoaming agent composition according to the present invention, it may adversely affect the appearance of a coating film painted using a water-based paint containing the defoaming agent composition. For this reason, the preferred embodiment of the defoaming agent composition according to the present invention does not contain silicone compounds.

[0106] (Form of the defoaming agent composition) The forms of the antifoaming agent composition according to the present invention include, specifically, a suspension in which organic solid fine particles (C) are suspended, a form in which an oily suspension is dispersed in a water-based medium (O(suspension) / W type emulsion), a form in which water-based droplets are dispersed in an oily suspension (W / O(suspension) type emulsion), and a form in which the above W / O(suspension) type emulsion is further dispersed in a water-based medium (W / O(suspension) / W type emulsion).

[0107] (Method for producing an antifoaming agent composition) The method for producing an antifoaming agent composition containing the above-mentioned components is not particularly limited, but in order to facilitate the production of a uniformly dispersed antifoaming agent composition and to exhibit excellent antifoaming properties, it is desirable to first prepare a preliminary dispersion of organic solid fine particles (C) (hereinafter referred to as "preliminary particle dispersion") and add it to the mixture of each component. It is desirable to add the preliminary particle dispersion while stirring with a disperser or the like. The stirring speed and stirring temperature can be appropriately set according to the dispersion state of the organic solid fine particles (C), etc. The method for preparing the preliminary particle dispersion is not particularly limited and can be prepared by methods known to those skilled in the art. As such methods, for example, there is a method in which an organic solid to be used as fine particles for organic solid fine particles (C) is melted at a predetermined temperature, and the molten liquid is poured into a container containing an organic medium (D), thereby precipitating the organic solid fine particles (C) while cooling in the organic medium (D), or a method in which organic solid fine particles (C) that have been adjusted to a predetermined particle size are suspended in the organic medium (D) and heated.

[0108] (Uses of antifoaming agent compositions) The defoaming agent composition according to the present invention is suitable for any application as long as it is added to water-based paints, but it is particularly suitable for applications requiring a high appearance and for use in multi-layer coating systems. For example, using the defoaming agent composition according to the present invention provides sufficient defoaming properties during the manufacturing, painting, and drying of water-based base coats for automobiles, water-based intermediate coats for automobiles, water-based primers for automobiles, water-based paints for high-grade furniture, floor paints, interior and exterior paints for buildings, anticorrosive paints, home appliances, etc., and prevents the occurrence of coating defects such as bubbling during the baking process. Furthermore, the defoaming agent composition according to the present invention can be suitably used in applications where paint raw materials that are difficult to disperse in water are used, or when the paint is circulated to prevent sedimentation and separation of components in the paint.

[0109] (Mechanism of action) The mechanism by which defoaming droplets and hydrophobic microparticles defoam is well known to those skilled in the art. It can be explained, for example, as follows: When defoaming droplets or hydrophobic microparticles penetrate the foam film, and the foam film thickness decreases due to drainage from the foam film, the defoaming components contained in the defoaming droplets or hydrophobic microparticles penetrate the foam film. Next, because the penetrating defoaming components are highly hydrophobic, the water tries to avoid them and the foam breaks. Hydrophobic microparticles are often used in combination with surfactants to give them a minimum affinity to water-based paint systems, but under high shear or prolonged shear, the surfactant detaches from the hydrophobic microparticles, exposing the hydrophobic surface. As a result, the hydrophobic microparticles cannot exist stably in water-based paints and aggregate. The aggregated hydrophobic microparticles do not redisperse, causing the formation of lumps, etc., or the effective concentration of microparticles to decrease, resulting in a loss of defoaming effect. Similarly, defoaming droplets are gradually miniaturized by shear force, and it is thought that they lose their defoaming effect when they can no longer maintain a size sufficient to penetrate the foam film.

[0110] On the other hand, the defoaming agent composition according to the present invention contains hydrophobic organic solid microparticles (C) within defoaming droplets composed of a nonionic surfactant (A), a defoaming polymer (B), and other defoaming components. Conventional compound-type defoamers have a similar configuration. However, the organic solid microparticles (C) in the present invention are organic materials with high affinity for the defoaming components, thereby retaining the defoaming components on the particle surface and preventing the hydrophobic surface of the microparticles from being exposed by shear force. Furthermore, even if the organic solid microparticles (C) are ejected from the defoaming droplets, a small amount of defoaming liquid remains on the surface of the microparticles. This allows them to be quickly protected and colloidalized by the nonionic surfactant (A), suppressing aggregation of the organic solid microparticles (C) and allowing the protected and colloidalized organic solid microparticles (C) to be re-incorporated into the defoaming droplets, thus returning to a form with excellent defoaming effect. This mechanism allows for the reconstruction of defoaming droplets around the protective colloidal particles, thus maintaining the defoaming effect, even when water-based paints containing defoaming agents are exposed to high shear or prolonged shear, causing defoaming droplets to become micronized or hydrophobic particles to detach from the defoaming droplets. To construct such a mechanism, appropriate selection and combination of materials—nonionic surfactant (A), polymer (B), and organic solid particles (C)—are necessary. Regarding the imparting of shear resistance through the above mechanism, it is even more desirable if the organic solid particles (C) have specific characteristics in shape. Specifically, (1) porous particles, (2) particles with uneven surfaces, and (3) microcrystalline clusters with specific aspect ratios are considered to exhibit superior shear resistance.

[0111] [Water-based paint composition] The water-based paint composition according to the present invention contains the above-described defoaming agent composition and a water-based resin as essential components. The water-based paint composition according to the present invention may further contain other paint raw materials as optional components, such as diluent solvents, pigments, dispersants, lubricants, emulsifiers, viscosity modifiers, film-forming aids, and pH adjusters.

[0112] (Content of defoaming agent) The content of the defoaming agent composition of the present invention varies depending on the type of water-based resin used as a binder in the water-based paint composition, the pigment blending composition, etc., but is generally preferably 0.1% to 5% by mass, and more preferably 0.5% to 2% by mass, relative to the water-based paint composition. If the content of the defoaming agent composition is less than 0.1% by mass, there is a risk that the additive effects of the defoaming agent composition of the present invention, such as defoaming properties and shear resistance, cannot be fully exhibited. On the other hand, if the content of the defoaming agent composition exceeds 5% by mass, it is undesirable because it may cause adverse effects such as poor interlayer adhesion when applying multiple coats of paint, uneven coating of the topcoat film, or poor water resistance of the paint film after drying.

[0113] (Water-based resin) The aqueous resin contained as a binder in the aqueous coating composition according to the present invention is a resin component dispersed in a water-based medium. Examples of resin components include acrylic resins, acrylic-silicone resins, alkyd resins, polyester resins, urethane resins, epoxy resins, silicone resins, and fluororesins. Aqueous resins can be classified into water-soluble, colloidal dispersion, and emulsion forms depending on their dispersion form, but any form is applicable. These resins may be heat-curable, UV-curable, electron-beam curable, oxidative-curable, photocationic-curable, peroxide-curable, or curable through a chemical reaction in or without a catalyst. They may also be resins with a high glass transition temperature that do not involve a chemical reaction and form a film simply by the volatilization of the diluent. Examples of curing agents include amino resins, melamine resins, isocyanate compounds, blocked isocyanate compounds, silane coupling agents, and epoxy compounds.

[0114] (Pigment) Examples of pigments include extender pigments such as calcium carbonate (heavy calcium carbonate (GCC), precipitated calcium carbonate (PCC), etc.), barium sulfate, silicon dioxide, aluminum hydroxide, talc, mica, organic fibers, and glass powder; coloring pigments such as titanium dioxide, carbon black, lead yellow, cadmium yellow, ochre, titanium yellow, zinc chromate, iron oxide, aluminosilicate, quinacridone, phthalocyanine, antroquinone, diketopyrrolopyrrole, benzimidazolon, and isoindolinone; and metallic pigments such as aluminum flakes, copper flakes, mica-like iron oxide, mica, and flaky powders of mica coated with metal oxides.

[0115] (Other additives) The water-based coating composition of the present invention may contain other additives, such as dispersants, lubricants, emulsifiers, viscosity modifiers, dehydrating agents (e.g., silane coupling agents), adhesion enhancers, surfactants, curing catalysts, film-forming aids, dryers, anti-fouling agents, sensitizers, antioxidants, light stabilizers, UV absorbers, water-resistant agents, anti-corrosion and anti-fungal agents, leveling agents, flame retardants, antistatic agents, release agents, deodorizers, pH adjusters, and fragrances, to the extent that its properties and the objectives of the present invention are not impaired.

[0116] In conventional water-based paints, surfactants are typically used as dispersants to disperse pigments in the paint, wetting agents to improve the wettability and smoothness of pigments, emulsifiers to emulsify non-aqueous resins, and viscosity modifiers to control the fluidity of the paint. These surfactants generate unwanted foam during the manufacturing process and application of water-based paints. However, by incorporating the defoaming agent composition of the present invention into the water-based paint composition, it is possible to suppress the generation and persistence of foam, and to maintain excellent defoaming properties even when high shear forces are applied to the paint. As a result, a paint film with an excellent painted appearance can be formed without hindering topcoatability.

[0117] (Method for manufacturing water-based paint compositions) The water-based paint composition of the present invention can be manufactured in accordance with known methods for manufacturing water-based paints. For example, the components other than the defoaming agent composition and pigment described above can be mixed while stirring in a water-based medium such as deionized water, and then the pH can be adjusted as necessary to produce a clear paint. The defoaming agent composition and pigment can then be added to this clear paint and dispersed within it to produce the water-based paint composition.

[0118] The timing for adding the defoaming agent composition according to the present invention to the water-based paint may be during the pigment mixing process as described above, or it may be added after the water-based paint has been manufactured, or it may be added after creating a masterbatch. Furthermore, the equipment used for dispersing the defoaming agent composition and pigment can be the same as that commonly used in the manufacture of water-based paints. In addition, the stirring speed and stirring time during the dispersion of the defoaming agent composition and pigment are not particularly limited and can be set as appropriate while checking the dispersion state of the defoaming agent composition and pigment.

[0119] (Uses of water-based paint compositions) The water-based paint composition of the present invention is particularly suitable for applications requiring a high appearance and for use in coating systems with multi-layer coatings. Examples of such applications include coatings for automotive materials, high-end furniture materials, floor coatings, interior and exterior building coatings, anticorrosive coatings, and home appliance coatings. Furthermore, the water-based paint composition of the present invention is also suitable for applications where paint raw materials that are difficult to disperse in water are used, or when the paint is circulated to prevent sedimentation and separation of components in the paint.

[0120] [Goods] The article according to the present invention has a substrate surface coated with a coating agent containing the above-described defoaming agent composition. That is, the article according to the present invention consists of a substrate and a coating film obtained by coating its surface with the coating agent.

[0121] (base material) The base material for the article according to the present invention is not particularly limited, but examples include base materials made of metal, plastic, wood, rubber, glass, stone, cement, mortar, paper, nonwoven fabric, cloth, and ceramics.

[0122] (coating film) The coating film of the article of the present invention can be obtained, for example, by applying the above-described water-based paint composition to the substrate and then curing it. The coating film formed on the surface of the substrate may be a single layer or a laminate of multiple coating films. Since the water-based paint composition containing the defoaming agent composition of the present invention has excellent defoaming properties and shear resistance, even when the water-based paint composition is used in applications requiring extremely high quality appearance and topcoatability, a satisfactory coating film appearance can be obtained without impeding topcoatability.

[0123] (Coating agent) Examples of the coating agent of the present invention used for coating the above-mentioned substrate include the water-based paint composition described above.

[0124] (Method of manufacturing articles) The articles of the present invention can be manufactured by applying a coating agent, such as the water-based paint composition of the present invention, to the above-mentioned substrate, and then drying and curing it. The method of applying the coating agent is not particularly limited and includes, for example, spray coating, roll coating, brush coating, curtain coating, bar coating, doctor blade coating, slit coating, dip coating, flow coating, etc. The method of curing the coating agent is not particularly limited and includes, for example, room temperature curing, heat curing, ultraviolet curing, etc.

[0125] Furthermore, when forming multiple coating films (multilayer coating films) on an article of the present invention, for example, this includes a coating film (primer coating film) obtained by applying the water-based paint composition of the present invention to a substrate, and a topcoat coating film laminated on all or part of the surface of the primer coating film. The topcoat paint may be the same as the paint used for the primer coating film, or it may be a different paint. Also, when forming a multilayer coating film, the topcoat may be applied after the primer coating has completely dried or hardened, or the topcoat may be applied when the primer coating has partially dried or hardened to the extent that it is not disturbed by the topcoat coating. Because the water-based paint composition containing the defoaming agent composition of the present invention has excellent topcoatability, even when the water-based paint composition is used in applications where extremely high quality appearance and topcoatability are required, the interlayer adhesion between the coating film obtained by the water-based paint composition and the topcoat coating film is excellent.

[0126] When forming a multilayer coating on an article of the present invention, the multilayer coating is formed, for example, by coating all or part of the surface of a coating obtained by curing a water-based primer paint to which the defoaming agent composition of the present invention has been added with a topcoat paint. Alternatively, the topcoat paint may be applied wet-on-wet without curing the water-based primer paint to which the defoaming agent composition of the present invention has been added, and then the primer and topcoat paints may be cured simultaneously. In this case, preferably, after applying the water-based primer paint to which the defoaming agent composition of the present invention has been added, unnecessary solvents (volatile components such as water and organic solvents) are removed without curing the water-based primer paint by air drying, air blowing, or preheat drying as necessary, and then the topcoat paint is applied. Preheat drying is particularly preferred as a drying method for the water-based primer paint.

[0127] Furthermore, the application method and curing method for the topcoat paint are not particularly limited, and the same methods as described above can be used.

[0128] (Use of the item) The articles of the present invention are particularly suitable for applications requiring a high level of appearance and for use in coating systems with multiple layers of coating film. Examples of such applications include automotive parts, high-end furniture, and home appliances.

[0129] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. That is, other embodiments or various modifications that a person skilled in the art could conceive of within the scope of the invention as described in the claims are also understood to fall within the technical scope of the present invention.

[0130] Specifically, the inventions include the following: (1) An antifoaming agent composition for water-based paints, comprising: (A) a nonionic surfactant having at least one hydrophilic portion selected from the group consisting of an ethylene glycol portion, a polyethylene glycol portion, and a polyhydric alcohol portion in its molecule, and having an HLB of 1 to 16; (B) a polymer that does not have the hydrophilic portion in its molecule, has an SP value of 7.5 to 12, and a weight-average molecular weight of 400 to 1,000,000; and (C) organic solid fine particles that are in a solid state in the antifoaming agent composition at 25°C. (2) The defoaming agent composition according to (1), characterized in that the nonionic surfactant (A) is one or more selected from the group consisting of ethylene glycol aliphatic ether, polyoxyalkylene aliphatic ether, polyoxyalkylene aromatic ether, polyoxyalkylene fatty acid ester, alkylene oxide addition derivative of castor oil, alkylene oxide addition derivative of hydrogenated castor oil, polyoxyalkylene polyhydric alcohol ether, polyhydric alcohol fatty acid ester, alkylene oxide addition derivative of polyhydric alcohol fatty acid ester, polyoxyalkylene alkylamide, acetylene glycol and its derivatives, alkylene oxide addition derivative of acetylene glycol, polyoxyethylene-polyoxypropylene block copolymer, and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer. (3) The defoaming agent composition according to (1) or (2), characterized in that the polymer (B) is one or more polymers selected from the group consisting of polyvinyl alkyl ether, polybutadiene, polybutene, polyisoprene, polyalphaolefin, polyalkyl (meth)acrylate, a copolymer of a dibasic acid ester, polyfatty acid vinyl ester, and a copolymer of alkyl (meth)acrylate and a fatty acid vinyl ester. (4) The defoaming agent composition according to any one of (1) to (3), characterized in that the organic solid fine particles (C) are one or more solid fine particles selected from the group consisting of amides, ureas, polyethylene, oxidized polyethylene, acid-modified polyethylene, and hydrogenated castor oil. (5) The antifoaming agent composition according to (4), characterized in that the amide is a fatty acid diamide obtained by reacting fatty acids selected from the group consisting of alkyl fatty acids and hydroxy fatty acids, including at least one hydroxy fatty acid, with diamines including one or more diamines selected from the group consisting of alkylenediamines having 2 to 6 carbon atoms and m-xylylenediamine. (6) The defoaming agent composition according to any one of (1) to (5), characterized in that the aspect ratio of the crystals of the organic solid fine particles (C) is 1.1 to 100. (7) The defoaming agent composition according to any one of (1) to (6), characterized in that the peak particle size (mode diameter) of the organic solid fine particles (C) is 0.1 to 150 μm. (8) The defoaming agent composition according to any one of (1) to (7), characterized in that it further contains an organic medium (D) other than water that does not have the hydrophilic portion in its molecule and is liquid at 25°C, and the weight-average molecular weight of the organic medium (D) is less than 400. (9) The defoaming agent composition according to (8), characterized in that the organic medium (D) is one or more selected from the group consisting of hydrocarbon oils, alcohols, glycol ethers and glycol esters. (10) The defoaming agent composition according to any one of (1) to (9), characterized in that it does not contain a silicone compound. (11) A water-based paint composition characterized by comprising an antifoaming agent composition described in any one of (1) to (10) and a water-based resin. (12) An article coated with a coating agent containing the defoaming agent composition described in any one of items (1) to (10). [Examples]

[0131] The present invention will be described in detail below with reference to examples. However, the present invention is not limited in any way to these examples. Furthermore, unless otherwise specified, "%" and "parts" in the examples refer to "mass%" and "parts by mass," respectively.

[0132] [Preparation of defoaming agent samples] Antifoaming agent samples E1-E54 and C1-C25 were prepared as follows.

[0133] (Preparation of nonionic surfactant) In this example and comparative example, the raw materials listed in Table 1 below were used as nonionic surfactant components, including nonionic surfactant (A). The HLB of the nonionic surfactant was determined by the Griffin method. Furthermore, raw materials labeled "A" in Table 1 are examples of nonionic surfactant (A) of the present invention, while raw materials labeled "non-A component" are raw materials that do not correspond to nonionic surfactant (A) of the present invention.

[0134] [Table 1]

[0135] (Polymer synthesis and preparation) In this example and the comparative examples, as the polymer component containing polymer (B), the raw materials described in Table 2 below were used. Note that the raw materials described as "B" as the component type in Table 2 are examples of the polymer (B) of the present invention, and the raw materials described as "non-B components" are raw materials that do not correspond to the polymer (B) of the present invention. The synthesis methods of the raw materials in Table 2 where the "source" is "synthesis method described in this application" are shown below.

[0136] <Synthesis of PEVE> As an example of polymer (B), polyethyl vinyl ether (hereinafter referred to as "PEVE") was synthesized by the method shown below. 150 parts of toluene and 3 parts of a boron trifluoride diethyl ether complex, which is a cationic polymerization initiator, diluted to 10% with diethyl ether were charged into a 1000 ml reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen gas inlet tube. After heating to 30 °C while introducing nitrogen gas, the following dropping solution (a) was uniformly dropped through the dropping funnel over 120 minutes. Dropping solution (a) 300 parts of ethyl vinyl ether 100 parts of toluene

[0137] 30 minutes after the completion of the dropping of the dropping solution (a), 15 parts of ethanol was added to stop the reaction. After the completion of the reaction, the solvent was removed using an evaporator to obtain a polymer (PEVE). The weight average molecular weight of the synthesized polymer was 3000 (SP value: 8.6).

[0138] <Synthesis of Acrylic Polymer 1> 95.0 parts of butyl acetate and 159.4 parts of dibutyl fumarate were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to 140°C (reflux) while stirring under a nitrogen gas stream. A mixture consisting of 28.1 parts of dibutyl fumarate, 187.5 parts of ethyl acrylate, 30.0 parts of 55% solution of 2,2-di(tert-amyl peroxy)butane and 7.5 parts of 2-ethylhexyl thioglycolate was charged into the dropping funnel as a dropping solution. Next, the dropping solution was uniformly added dropwise over 120 minutes while maintaining the internal temperature of the reaction vessel under reflux. After the addition was complete, the reaction temperature was maintained under reflux for 120 minutes to allow the reaction to proceed. After the reaction was complete, the solvent was removed using an evaporator to obtain acrylic copolymer 1. The weight-average molecular weight of the synthesized copolymer was 3500 (SP value: 10.1).

[0139] <Synthesis of polyneodecanoate vinyl ester> 104.6 parts of butyl acetate were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to reflux conditions for the butyl acetate while stirring under a nitrogen gas stream. A mixture consisting of 375.0 parts of vinyl neodecanoate (trade name Beova 10: manufactured by HEXON) and 20.5 parts of 55% 2,2-di(tert-amylperoxy)butane solution was charged into the dropping funnel as the dropping solution. Next, while maintaining the internal temperature of the reaction vessel under reflux, the dropping solution was uniformly added dropwise over 120 minutes. After the addition was complete, the reaction temperature was maintained under reflux for 60 minutes to allow the reaction to proceed. After the reaction was complete, the solvent was removed using an evaporator to obtain polyneodecanoate vinyl ester. The weight-average molecular weight of the synthesized copolymer was 7900 (SP value: 9.0).

[0140] <Synthesis of Acrylic Polymer 2> 197.5 parts of isoparaffinic solvent (product name Merveille 30: Idemitsu Kosan Co., Ltd.) were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to 95°C while stirring under a nitrogen gas stream. A mixture consisting of 250.0 parts lauryl methacrylate, 49.4 parts of isoparaffinic solvent (product name Merveille 30: Idemitsu Kosan Co., Ltd.), and 3.1 parts of 40% tert-butyl peroxy-2-ethylhexanoate solution was charged into the dropping funnel as a dropping solution. Next, the dropping solution was uniformly added dropwise over 75 minutes while maintaining the internal temperature of the reaction vessel at 95°C. After the dropwise addition was complete, the reaction temperature was maintained at 95°C for 60 minutes, and then 0.7 parts of 40% tert-butyl peroxy-2-ethylhexanoate solution was added and the temperature was maintained at 95°C for 45 minutes. Subsequently, the internal temperature of the reaction vessel was raised to 100°C and the reaction was carried out for 30 minutes. After the reaction was complete, the heat residue was adjusted to 50% with an isoparaffinic solvent (product name Merveille 30: Idemitsu Kosan Co., Ltd.) to obtain acrylic copolymer 2. The weight-average molecular weight of the synthesized copolymer was 178,900 (SP value: 9.0).

[0141] <Synthesis of Acrylic Polymer 3> 188.5 parts of isoparaffinic solvent (product name Merveille 30: Idemitsu Kosan Co., Ltd.) were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to 95°C while stirring under a nitrogen gas stream. A mixture consisting of 250.0 parts lauryl methacrylate, 47.1 parts of isoparaffinic solvent (product name Merveille 30: Idemitsu Kosan Co., Ltd.), and 12.5 parts of 40% tert-butyl peroxy-2-ethylhexanoate solution was charged into the dropping funnel as a dropping solution. Next, the dropping solution was uniformly added dropwise over 75 minutes while maintaining the internal temperature of the reaction vessel at 95°C. After the dropwise addition was complete, the reaction temperature was maintained at 95°C for 60 minutes, and then 0.7 parts of 40% tert-butyl peroxy-2-ethylhexanoate solution was added and the temperature was maintained at 95°C for 45 minutes. Subsequently, the internal temperature of the reaction vessel was raised to 100°C and the reaction was carried out for 30 minutes. After the reaction was complete, the heat residue was adjusted to 50% with an isoparaffinic solvent (product name Merveille 30: Idemitsu Kosan Co., Ltd.) to obtain acrylic copolymer 3. The weight-average molecular weight of the synthesized copolymer was 74100 (SP value: 9.0).

[0142] <Synthesis of Acrylic Polymer 4> 350.0 parts of methylpropylene glycol were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to 120°C while stirring under a nitrogen gas stream. A mixture consisting of 75.0 parts of acrylic acid, 50.0 parts of styrene, 25.0 parts of 50% tert-amyl peroxy-2-ethylhexanoate solution, and 6.3 parts of 2-ethylhexyl thioglycolate was charged into the dropping funnel as a dropping solution. Next, the dropping solution was uniformly added dropwise over 120 minutes while maintaining the internal temperature of the reaction vessel at 120°C. After the addition was complete, the reaction temperature was maintained at 120°C for 60 minutes, and then 0.8 parts of 50% tert-amyl peroxy-2-ethylhexanoate solution was added and the reaction was carried out for 30 minutes while maintaining the temperature at 120°C. After the reaction was complete, the solvent was removed using an evaporator to obtain acrylic copolymer 4. The weight-average molecular weight of the synthesized copolymer was 3600 (SP value: 12.4).

[0143] <Synthesis of Acrylic Polymer 5> 200.0 parts of butyl acetate were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to the reflux state of butyl acetate while stirring under a nitrogen gas stream. A mixture consisting of 250.0 parts of ethyl acrylate and 50.0 parts of 50% tert-amyl peroxy-2-ethylhexanoate solution was charged into the dropping funnel as the dropper solution. Next, while maintaining the internal temperature of the reaction vessel under reflux, the dropper solution was uniformly added dropwise over 100 minutes. After the dropper addition was complete, the reaction temperature was maintained under reflux for 60 minutes, and then 1.5 parts of 50% tert-amyl peroxy-2-ethylhexanoate solution was added dropwise and the reaction was carried out for 30 minutes. After the reaction was complete, the solvent was removed using an evaporator to obtain acrylic copolymer 5. The weight-average molecular weight of the synthesized copolymer was 3900 (SP value: 10.2).

[0144] <Synthesis of Acrylic Polymer 6> 108.0 parts of butyl acetate were charged into a 1000 mL reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet tube. The internal temperature was then raised to the reflux state of butyl acetate while stirring under a nitrogen gas stream. A mixture consisting of 375.0 parts of 2-ethylhexyl acrylate and 17.2 parts of 55% 2,2-di(tert-amyl peroxy)butane solution was charged into the dropping funnel as the dropping solution. Next, while maintaining the internal temperature of the reaction vessel under reflux, the dropping solution was uniformly added dropwise over 120 minutes. After the dropping was complete, the reaction temperature was maintained under reflux for 60 minutes to allow the reaction to proceed. After the reaction was complete, the solvent was removed using an evaporator to obtain acrylic copolymer 6. The weight-average molecular weight of the synthesized copolymer was 7800 (SP value: 9.2).

[0145] The SP values ​​of the polymers shown in Table 2 were calculated using Fedors' method. For the measurement of the weight-average molecular weight of the polymers shown in Table 2, an HLC-8320GPC (Tosoh Corporation) was used as the measuring instrument. The columns used were TSKgel GMHxl×2, TSKgel G2500Hxl, TSKgel G2000Hxl, and TSKgel guardcolumn (all Tosoh Corporation). Tetrahydrofuran (THF) was used as the mobile phase, the column temperature was set to 40°C, the flow rate to 1 mL / min, and an RI detector was used. The weight-average molecular weights shown in Table 2 were calculated from the chromatographs measured by gel permeation chromatography (GPC), using the molecular weight of standard polystyrene as a reference.

[0146] [Table 2]

[0147] (Preparation and manufacturing of solid microparticles) In this embodiment and comparative example, the raw materials listed in Table 3 below were used as solid particle components containing organic solid particles (C). In Table 3, raw materials labeled "C" are examples of the organic solid particles (C) of the present invention, while raw materials labeled "non-C component" are raw materials that do not correspond to the organic solid particles (C) of the present invention. The manufacturing methods for the raw materials listed in Table 3 as "Source" and "Manufacturing Method Described in this Application" are shown below. Specifically, fine particles OC-1 to OC-18, which are examples of organic solid particles (C), were manufactured by the method described below.

[0148] <oc-1> Step 0 involved reacting 2 moles of 12-hydroxystearic acid (12-HSA) and 1 mole of hexamethylenediamine under a nitrogen gas stream at 190°C for 6 hours, removing the water produced to obtain diamide (a1). Next, a mixture of 10 parts of diamide (a1) as a fine particle component and 90 parts of Merveille 30 (isoparaffin manufactured by Idemitsu Kosan Co., Ltd.) as an organic medium (D) (fine particle mixture) was heated to 165°C using a heater to dissolve the diamide (a1) in Merveille 30 by heating, obtaining a fine particle solution (Step 1). Additionally, 60 parts of Merveille 30 were placed in a 500 mL container, and the fine particle solution was poured in under stirring. The mixture was then cooled to a temperature of 97.0°C (Step 2). After cooling the mixture containing the fine particle solution to around 30°C, 40 parts of ethanol were added to the mixture and stirred (Step 3). Next, while maintaining stirring, the temperature of the mixture was adjusted to 46.5°C, and stirring was continued for 12 minutes to obtain a preliminary dispersion of fine particles OC-1 (step 4).

[0149] <oc-2> In step 0, 2 moles of 12-HSA and 1 mole of ethylenediamine were reacted to obtain diamide (a2). In step 1, diamide (a2) was used instead of diamide (a1), and the fine particle mixture was heated to 155°C. In step 2, the mixture was cooled to 88.0°C after mixing, and in step 4, the temperature of the mixture was adjusted to 48.5°C. Except for these differences, a preliminary dispersion of fine particle OC-2 was obtained in the same manner as for OC-1.

[0150] <oc-3> In step 0, 2 moles of 12-HSA and 1 mole of 1,4-diaminobutane were reacted to obtain diamide (a3). In step 1, diamide (a3) ​​was used instead of diamide (a1), and the fine particle mixture was heated to 160°C. In step 2, the mixture was cooled to 97.0°C after mixing, and in step 4, the temperature of the mixture was adjusted to 42.0°C. A preliminary dispersion of fine particle OC-3 was obtained in the same manner as OC-1.

[0151] <oc-4> A preliminary dispersion of fine particles OC-4 was obtained in the same manner as for OC-3, except that in step 2 the mixture was cooled to a temperature of 92.5°C, and in step 4 the temperature of the mixture was adjusted to 45.3°C.

[0152] <oc-5> A preliminary dispersion of fine particles OC-5 was obtained in the same manner as OC-1, except that hydrogenated castor oil was used instead of diamide (a1), the fine particle mixture was heated to 95°C in step 1, the temperature after mixing was cooled to 53.9°C in step 2, and step 4 was not performed.

[0153] <oc-6> A preliminary dispersion of fine particles OC-6 was obtained in the same manner as OC-1, except that butyl glycol was used as the organic medium (D) in steps 1 and 2, the fine particle mixture was heated to 120°C, the temperature after mixing was cooled to 25.0°C in step 2, and step 4 was not performed.

[0154] <oc-7> A preliminary dispersion of fine particles OC-7 was obtained in the same manner as OC-1, except that low-density polyethylene oxide (product name "AC 629" manufactured by Honeywell Japan Ltd.) was used instead of diamide (a1), the fine particle mixture was heated to 150°C in step 1, the temperature after mixing was cooled to 46.7°C in step 2, and step 4 was not performed.

[0155] <oc-8> A preliminary dispersion of fine particles OC-8 was obtained in the same manner as for OC-1, except that in step 2 the mixture was cooled to 47.7°C, and in step 4 the temperature of the mixture was adjusted to 38.7°C.

[0156] <oc-9> A preliminary dispersion of fine particles OC-9 was obtained in the same manner as for OC-1, except that in step 2 the mixture was cooled to a temperature of 44.7°C, and in step 4 the temperature of the mixture was adjusted to 40.3°C.

[0157] <oc-10> A preliminary dispersion of fine particles OC-10 was obtained in the same manner as for OC-1, except that in steps 1 and 2, 2-ethylhexanol was used as the organic medium (D), the fine particle mixture was heated to 135°C, in step 2 the temperature after mixing was cooled to 51.4°C, and in step 4 the temperature of the mixture was adjusted to 57.7°C.

[0158] <oc-11> A preliminary dispersion of fine particles OC-11 was obtained in the same manner as for OC-1, except that in steps 1 and 2, 2-ethylhexanol was used as the organic medium (D), the fine particle mixture was heated to 135°C, in step 2 the mixture was cooled to 45.5°C after mixing, and in step 4 the temperature of the mixture was adjusted to 62.1°C.

[0159] <oc-12> A preliminary dispersion of fine particles OC-12 was obtained in the same manner as for OC-1, except that methylpropylene glycol was used as the organic medium (D) in steps 1 and 2, the fine particle mixture was heated to 110°C, the temperature after mixing was cooled to 48.5°C in step 2, and the temperature of the mixture was adjusted to 50.4°C in step 4.

[0160] <oc-13> A preliminary dispersion of fine particles OC-13 was obtained in the same manner as for OC-2, except that in step 2 the mixture was cooled to 37.4°C, and in step 4 the temperature of the mixture was adjusted to 61.3°C.

[0161] <oc-14> A preliminary dispersion of fine particles OC-14 was obtained in the same manner as for OC-1, except that methylpropylene glycol was used as the organic medium (D) in steps 1 and 2, the fine particle mixture was heated to 110°C, the temperature after mixing was cooled to 38.5°C in step 2, and the temperature of the mixture was adjusted to 57.4°C in step 4.

[0162] <oc-15> After step 3, instead of step 4, the mixture obtained in step 3 was placed in a bottle and heated to 70°C over 24 hours, and maintained at that temperature for 24 hours. Then, a preliminary dispersion of fine particles OC-15 was obtained in the same manner as for OC-1, except that it was subsequently cooled to 25°C over 24 hours.

[0163] <oc-16> After step 3, instead of step 4, the mixture obtained in step 3 was placed in a bottle and heated to 80°C over 24 hours, and maintained at that temperature for 24 hours. Then, a preliminary dispersion of fine particles OC-16 was obtained in the same manner as for OC-1, except that it was cooled down to 25°C over 24 hours.

[0164] <oc-17> A preliminary dispersion of fine particles OC-17 was obtained in the same manner as for OC-2, except that in step 2 the mixture was cooled to a temperature of 45.6°C, and in step 4 the temperature of the mixture was adjusted to 45.5°C.

[0165] <oc-18> In step 0, 2 moles of 12-HSA and 1 mole of m-xylylenediamine were reacted to obtain diamide (a4). In step 1, diamide (a4) was used instead of diamide (a1), and the fine particle mixture was heated to 150°C. In step 2, the mixture was cooled to 46.5°C after mixing, and in step 4, the temperature of the mixture was adjusted to 47.3°C. Except for these differences, a preliminary dispersion of fine particle OC-18 was obtained in the same manner as OC-1.

[0166] <Measurement of peak particle size> For the fine particles OC-1 to OC-18 obtained as described above, the peak particle size was measured using a Microtrac MT-3000EXII / USVR particle size distribution analyzer (Microtrac Corporation) with Merveille 30 as the circulating solvent. The peak particle size (μm) of each organic solid fine particle is shown in Table 3.

[0167] <Aspect Ratio Measurement> The aspect ratios of the fine particles OC-1 to OC-18 obtained as described above were measured as follows (1) to (7). 1) A preliminary dispersion of fine particles OC-1 to OC-18 was diluted 300 times with xylene, and the fine particles were dispersed in the diluted solution by irradiating it with ultrasound for 30 seconds. 2) One drop of the diluted solution from 1) was placed on a copper microgrid (grid pitch 150 μm) with a carbon-reinforced collodion support film on filter paper and allowed to air dry. 3) The microgrid containing the fine particle sample obtained in 2) was fixed onto the SEM mount using carbon tape. 4) SEM measurements were performed using the following conditions: Measurement device: SU3500 (manufactured by Hitachi High-Technologies Corporation), Measurement mode: High vacuum / low acceleration voltage, Image: Backscattered electron image, Magnification: 2,000x, Brightness / Contrast: Auto, Focus: Manual. 5) Image analysis was performed using image analysis software (ImageJ). After brightness / contrast correction and smoothing, the image was binarized, noise, image boundary particles, and aggregated particles were removed, and particle analysis was performed. 6) If the particles to be measured consist only of non-convex shapes, particle analysis was performed, and the aspect ratio (= major axis value / minor axis value) was calculated from the major axis value and minor axis value of each particle obtained. The average of the aspect ratios of 10 or more particles was taken as the aspect ratio of the fine particle sample (fine particles OC-1 to OC-18). 7) If the particles to be measured include both convex and non-convex shapes, the fiber length was measured using the Freehand line tool and the fiber width at the center of the particle was measured using the Straight line tool. The aspect ratio (= fiber length value / fiber width value) was calculated, and the average of the aspect ratios of 10 or more particles was taken as the aspect ratio of the sample.

[0168] Furthermore, "non-convex shape" refers to particles where the area of ​​the convex hull (the part enclosed by a contractile virtual curve) is more than twice the actual area. Conversely, "convex shape" refers to particles where the area of ​​the convex hull is less than twice the actual area. The aspect ratios of each organic solid microparticle are shown in Table 3.

[0169] [Table 3]

[0170] (Preparation of organic media) In this example and comparative example, the raw materials listed in Table 4 below were used as the organic medium (D). The boiling points of some of the raw materials are also listed in Table 4.

[0171] [Table 4]

[0172] (Preparation of defoaming agent samples) Antifoaming agent samples E1-E54 and C1-C25 were prepared using the method described below. The details of the preparation method for each antifoaming agent sample are shown below.

[0173] <Antifoaming agent sample E1> In a 100 mL poly cup, 7.5 parts of EMALEX RWIS-305 (PEG-5 hydrogenated castor oil triisostearate manufactured by Nippon Emulsion Co., Ltd.) and 27.5 parts of PEVE were charged. While stirring with a disperser, 30.0 parts of a preliminary dispersion of fine particles OC-1 were added, and the mixture was stirred at 2000 rpm for 15 minutes to obtain the antifoaming agent sample E1.

[0174] <Antifoaming agent sample E2> Antifoaming agent sample E2 was obtained using the same method as for antifoaming agent sample E1, except that the predispersion of fine particles OC-1 was changed to a predispersion of fine particles OC-2.

[0175] <Antifoaming agent sample E3> Antifoaming agent sample E3 was obtained using the same method as for antifoaming agent sample E1, except that the predispersion of fine particles OC-1 was replaced with a predispersion of fine particles OC-3.

[0176] <Antifoaming agent sample E4> Except for changing EMALEX RWIS-305 to EMALEX RWIS-330 (PEG-30 hydrogenated castor oil triisostearate manufactured by Nippon Emulsion Co., Ltd.), defoaming agent sample E4 was obtained using the same method as defoaming agent sample E1.

[0177] <Antifoaming agent sample E5> Except for replacing EMALEX RWIS-305 with Brownon CW-3 (PEG-3 hydrogenated castor oil manufactured by Aoki Oil & Fat Industry Co., Ltd.), defoaming agent sample E5 was obtained using the same method as defoaming agent sample E1.

[0178] <Antifoaming agent sample E6> Except for replacing EMALEX RWIS-305 with Brownon CW-3 (PEG-3 hydrogenated castor oil manufactured by Aoki Oil & Fat Industry Co., Ltd.), defoaming agent sample E6 was obtained using the same method as defoaming agent sample E2.

[0179] <Antifoaming agent sample E7> Except for replacing EMALEX RWIS-305 with Brownon CW-3 (PEG-3 hydrogenated castor oil manufactured by Aoki Oil & Fat Industry Co., Ltd.), the same method as for defoaming agent sample E3 was used to obtain defoaming agent sample E7.

[0180] <Antifoaming agent samples E8~E18> Except for changing EMALEX RWIS-305 to "A: Nonionic surfactant" as described in Table 6, and changing polymer (B) to Durasyn164, defoaming agent samples E8 to E18 were obtained using the same method as defoaming agent sample E1.

[0181] <Antifoaming agent sample E19> Antifoaming agent sample E19 was obtained in the same manner as antifoaming agent sample E1, except that 27.5 parts of PEVE were changed to 10.3 parts of PEVE and 3.4 parts of RB810, and the polymer (PEVE and RB810) was diluted with 30 parts of Merveille and 13.8 parts before being mixed with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1.

[0182] <Antifoaming agent sample E20> Antifoaming agent sample E20 was obtained in the same manner as antifoaming agent sample E1, except that 27.5 parts of PEVE were replaced with 1:22.0 parts of acrylic polymer, the polymer (acrylic polymer 1) was diluted with 5.5 parts of 2-ethylhexanol, and then mixed with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-10.

[0183] <Antifoaming agent samples E21, E22, E24~E26> Except for changing PEVE to "B: Polymer" as described in Table 7, defoaming agent samples E21, E22, and E24-E26 were obtained using the same method as for defoaming agent sample E1.

[0184] <Antifoaming agent sample E23> Except for changing EMALEX RWIS-305 to EMALEX RWIS-320 (PEG-20 hydrogenated castor oil triisostearate manufactured by Nippon Emulsion Co., Ltd.) and changing PEVE to vinyl ester polyneodecanoate, defoaming agent sample E23 was obtained using the same method as defoaming agent sample E1.

[0185] <Antifoaming agent sample E27> Antifoaming agent sample E27 was obtained in the same manner as antifoaming agent sample E1, except that 27.5 parts of PEVE were replaced with 27.5 parts of a solution of acrylic polymer 2 in Merveille 30 (solvent) (polymer concentration: 50% by mass), and mixed with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1.

[0186] <Antifoaming agent sample E28> Antifoaming agent sample E28 was obtained in the same manner as antifoaming agent sample E1, except that 27.5 parts of PEVE were replaced with 27.5 parts of a solution of acrylic polymer 3 in Merveille 30 (solvent) (polymer concentration: 50% by mass), and mixed with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1.

[0187] <Antifoaming agent sample E29> Antifoaming agent sample E29 was obtained in the same manner as antifoaming agent sample E1, except that 27.5 parts of PEVE were replaced with 18.6 parts of LUTONAL I 60 (a solvent naphtha solution with a PIBVE concentration of 80% by mass), which is polyisobutyl vinyl ether (PIBVE) manufactured by BASF, and the polymer (LUTONAL I 60) was diluted with 8.9 parts of Merveille 30 before being mixed with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1.

[0188] <Antifoaming agent sample E30> Antifoaming agent sample E30 was obtained in the same manner as antifoaming agent sample E1, except that 27.5 parts of PEVE were replaced with 11.5 parts of LUTONAL I 60 (a solvent naphtha solution with a PIBVE concentration of 80% by mass), the polymer (LUTONAL I 60) was diluted with 16.0 parts of Merveille 30, and then mixed with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1.

[0189] <Antifoaming agent sample E31> Except for replacing 27.5 parts of PEVE with 15.3 parts of PIBVE (an isoparaffin solution with a PIBVE concentration of 60% by mass) manufactured by Siwei, and diluting the polymer (PIBVE manufactured by Siwei) with 12.2 parts of Merveille 30 before mixing it with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1, defoamer sample E31 was obtained in the same manner as defoamer sample E1.

[0190] <Antifoaming agent samples E32~E44> Except for changing the preliminary dispersion of fine particles OC-1 to "C: Organic solid fine particles (fine particles OC-4 to OC-16)" as listed in Table 8, defoaming agent samples E32 to E44 were obtained using the same method as for defoaming agent sample E1.

[0191] <Antifoaming agent sample E45> Except for changing PEVE:27.5 parts to acrylic polymer 5:22.0 parts, diluting the polymer (acrylic polymer 5) with 2-ethylhexanol:5.5 parts, and then mixing it with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-10, defoaming agent sample E45 was obtained in the same manner as defoaming agent sample E1.

[0192] <Antifoaming agent samples E46~E54> Except for changing EMALEX RWIS-305 to "A: Nonionic surfactant" as listed in Table 9, changing PEVE to "B: Polymer" as listed in Table 9, and changing the preliminary dispersion of fine particles OC-1 to "C: Organic solid fine particles" as listed in Table 9, defoaming agent samples E46 to E54 were obtained using the same method as defoaming agent sample E1.

[0193] <Antifoaming agent sample C1> Antifoaming agent sample C1 was obtained in the same manner as antifoaming agent sample E1, except that Merveille 30 was used instead of the pre-dispersion of fine particles OC-1.

[0194] <Antifoaming agent sample C2> Antifoaming agent sample C2 was obtained in the same manner as antifoaming agent sample E4, except that Merveille 30 was used instead of the predispersion of fine particles OC-1.

[0195] <Antifoaming agent sample C3> Antifoaming agent sample C3 was obtained using the same method as antifoaming agent sample E5, except that Merveille 30 was used instead of the pre-dispersion of fine particles OC-1.

[0196] <Antifoaming agent sample C4> Antifoaming agent sample C4 was obtained using the same method as antifoaming agent sample E1, except that Merveille 30 was used instead of EMALEX RWIS-305 and PEVE.

[0197] <Antifoaming agent sample C5> Antifoaming agent sample C5 was obtained using the same method as antifoaming agent sample E2, except that Merveille 30 was used instead of EMALEX RWIS-305 and PEVE.

[0198] <Antifoaming agent sample C6> Antifoaming agent sample C6 was obtained using the same method as antifoaming agent sample E3, except that Merveille 30 was used instead of EMALEX RWIS-305 and PEVE.

[0199] <Antifoaming agent sample C7> As the defoaming agent sample C7, we used BYK-024 (manufactured by BYK), which is a mixture of silicone, hydrophobic microparticles, and polyglycol.

[0200] <Antifoaming agent sample C8> As the defoaming agent sample C8, we used Agitan295 (manufactured by MUNZING CHEMIE GmbH), which is a mixture of hydrocarbons, hydrophobic silica, and alkoxy compounds.

[0201] <Antifoaming agent samples C9-C14, C18> Except for changing EMALEX RWIS-305 to "A: Nonionic surfactant" or "Nonionic surfactant (non-A component)" as described in Table 11, and changing PEVE to "B: Polymer" or "Polymer (non-B component)" as described in Table 11, defoaming agent samples C9-C14 and C18 were obtained using the same method as for defoaming agent sample E1.

[0202] <Antifoaming agent sample C15> Except for replacing PEVE:27.5 parts with acrylic polymer 4:13.8 parts, diluting the polymer (acrylic polymer 4) with methylpropylene glycol:13.7 parts, and then mixing it with a preliminary dispersion of EMALEX RWIS-305 and fine particles OC-1, defoamer sample C15 was obtained in the same manner as defoamer sample E1.

[0203] <Antifoaming agent sample C16> Except for changing EMALEX RWIS-305 to EMALEX RWIS-330 (PEG-30 hydrogenated castor oil triisostearate manufactured by Nippon Emulsion Co., Ltd.), changing PEVE:27.5 parts to acrylic polymer 4:13.8 parts, diluting the polymer (acrylic polymer 4) with methylpropylene glycol:13.7 parts, and then mixing it with a preliminary dispersion of EMALEX RWIS-330 and fine particles OC-1, defoaming agent sample C16 was obtained in the same manner as defoaming agent sample E1.

[0204] <Antifoaming agent sample C17> 13.0 parts of FS1265-10000cst (fluorine-modified silicone manufactured by Dow Toray Corporation) were diluted with 32.5 parts of methyl isobutyl ketone to obtain a polymer diluent. Next, 6.5 parts of EMALEX RWIS-305 and the above polymer diluent were placed in a 100 mL poly cup, and while stirring with a disperser, 13.0 parts of a preliminary dispersion of fine particles OC-1 were added, followed by stirring at 2000 rpm for 15 minutes to obtain the antifoaming agent sample C17.

[0205] <Antifoaming agent sample C19> In a 100 mL poly cup, 7.4 parts of EMALEX RWIS-305, 27.2 parts of Durasyn 164 (polyalphaolefin, component B, manufactured by INEOS Oligmers), and 0.7 parts of KF-96-50CS (polydimethylsiloxane, non-component B, manufactured by Shin-Etsu Chemical Co., Ltd.) were charged. While stirring with a disperser, 29.7 parts of a preliminary dispersion of fine particles OC-1 were added, and the mixture was stirred at 2000 rpm for 15 minutes to obtain the antifoaming agent sample C19.

[0206] <Antifoaming agent sample C20> In a 100 mL poly cup, 1.2 parts of Sylophobic 100 (hydrophobic silica, non-C component, manufactured by Fuji Silicia Chemical Co., Ltd.), 5.8 parts of Nipsil SS-30P (hydrophobic silica, non-C component, manufactured by Tosoh Silica Co., Ltd.), and 93.0 parts of Cosmo Pure Spin G (hydrogen-purified paraffin, manufactured by Cosmo Oil Lubricants Co., Ltd.) were charged and mixed by stirring at 3500 rpm for 15 minutes to obtain defoaming agent sample C20 (silica-containing defoaming agent). For Sylophobic 100 and Nipsil SS-30P, the methanol wetting value (M value) and volume-average particle size were measured. The M value represents the degree of hydrophobicity; a higher M value indicates lower hydrophilicity, and it is expressed as the minimum volume ratio of methanol required to uniformly disperse hydrophobic fine particles in a water-methanol mixture. Here, the M value was determined by the following method. 0.2 g of the sample (Sylophobic 100 and Nipsil SS-30P) was ignited in 50 mL of water in a 250 mL beaker, and methanol was then added dropwise from a burette until the entire sample was suspended. During this process, the solution in the beaker was continuously stirred with a magnetic stirrer, and the endpoint was defined as the point when the entire sample was uniformly suspended in the solution. The volume percentage of methanol in the liquid mixture in the beaker at the endpoint was defined as the M value. For volume-average particle size, a Microtrac MT-3000EXII / USVR laser diffraction particle size analyzer was used, and the 50% integrated volume-average particle size was measured by circulating 2-propanol. The M values ​​and volume-average particle sizes of Sylophobic 100 and Nipsil SS-30P measured in this manner are as follows. Sylophobic 100 M value: 60, Volume average particle size: 2.4 μm Nipsil SS-30P M value: 60, Volume average particle size: 17.5 μm

[0207] <Antifoaming agent sample C21> In a 100 mL poly cup, 3.4 parts of EMALEX RWIS-305 and 12.5 parts of Durasyn 164 were charged. While stirring with a disperser, 13.6 parts of a preliminary dispersion of fine particles OC-1 and 9.7 parts of antifoaming agent sample C20 were added, and the mixture was stirred at 2000 rpm for 15 minutes to obtain antifoaming agent sample C21.

[0208] <Antifoaming agent sample C22> In a 100 mL poly cup, 3.4 parts of EMALEX RWIS-305, 12.5 parts of Durasyn 164, 10.2 parts of Merveille 30, and 2.8 parts of ethanol were charged. While stirring with a disperser, 9.7 parts of defoaming agent sample C20 were added, and the mixture was stirred at 2000 rpm for 15 minutes to obtain defoaming agent sample C22.

[0209] <Antifoaming agent sample C23> A silica slurry was prepared by charging 1.2 parts of Sylophobic 100 (hydrophobic silica, non-C component, manufactured by Fuji Silicia Chemical Co., Ltd.), 5.8 parts of Nipsil SS-30P (hydrophobic silica, non-C component, manufactured by Tosoh Silica Co., Ltd.), 73.4 parts of Merveille 30, and 19.6 parts of ethanol, and mixing them with a disperser at 2000 rpm for 15 minutes. Next, 4.6 parts of EMALEX RWIS-305, 16.9 parts of Durasyn 164, 13.8 parts of Merveille 30, and 3.7 parts of ethanol into a 100 mL poly cup, adding 13.1 parts of the silica slurry while stirring with a disperser, and then mixing with a disperser at 2000 rpm for 15 minutes to obtain the antifoaming agent sample C23.

[0210] <Antifoaming agent sample C24> After preparing a silica slurry in the same manner as for the antifoaming agent sample C23, 4.6 parts of EMALEX RWIS-305 and 16.9 parts of Durasyn 164 were placed in a 100 mL poly cup. While stirring with a disperser, 18.5 parts of a preliminary dispersion of fine particles OC-1 and 13.1 parts of silica slurry were added, and the mixture was stirred at 2000 rpm for 15 minutes to obtain the antifoaming agent sample C24.

[0211] <Antifoaming agent sample C25> In a 100 mL poly cup, 7.5 parts of EMALEX RWIS-305, 27.5 parts of Durasyn 164, 24.0 parts of Merveille 30, and 6.0 parts of ethanol were charged and mixed by stirring at 2000 rpm for 15 minutes to obtain the antifoaming agent sample C25.

[0212] The compositions of each antifoaming agent sample prepared as described above are shown in Tables 5 to 11 below.

[0213] [Table 5]

[0214] [Table 6]

[0215] [Table 7]

[0216] [Table 8]

[0217] [Table 9]

[0218] [Table 10]

[0219]

Table 11

[0220] (Preparation of Aqueous Paint Composition and Test Solution) Two types of aqueous paints (Blank) were prepared with the formulations shown in Table 12 and Table 13 below. The aqueous paint shown in Table 12 is an air-drying paint (a paint dried at room temperature), and the aqueous paint shown in Table 13 is a baking paint (a paint cured by heating).

[0221]

Table 12

[0222]

Table 13

[0223] <Preparation of Aqueous Paint Composition with Air-Drying Paint Formulation> Weighed 100 parts of the air-drying paint in Table 12 into a 300 mL glass tall beaker, and added 1 part each of defoamers E1 - E44 and C1 - C24 obtained as described above dropwise over 1 minute while stirring at 1000 rpm to obtain the aqueous paint compositions of Examples 1 - 44 (Table 14) and Comparative Examples 1 - 24 (Table 15).

[0224] <Preparation of Test Solution for Evaluation Test of Air-Drying Paint Formulation> The aqueous coating compositions obtained in Examples 1-44 and Comparative Examples 1-24 as described above were dispersed at 2000 rpm using a disperser equipped with a φ5 cm cowless blade (pre-shear process). For each aqueous coating composition, a dispersion liquid dispersed for 5 minutes (hereinafter sometimes referred to as "5-minute dispersion") and a dispersion liquid dispersed for 20 minutes (hereinafter sometimes referred to as "20-minute dispersion") were prepared. The 5-minute and 20-minute dispersions performed in this process correspond to a short-term high-shear process and a long-term high-shear process, respectively. The test liquid dispersed for 20 minutes showed a higher specific gravity recovery rate, indicating superior shear resistance.

[0225] <Preparation of water-based paint compositions containing baking paint: for 5-minute dispersions> 100 parts of the baking paints shown in Table 13 were weighed into a 300 mL tall glass beaker. To this, 1 part each of the defoaming agents E9, E11-13, E15, E18, E24, E27, E32, E33, E45-E54, and C15, C20, C23, and C25, obtained as described above, were added dropwise over 1 minute while stirring at 1000 rpm to obtain the aqueous paint compositions (for 5-minute dispersions) of Examples 45-64 and Comparative Examples 25-28 (all in Table 16).

[0226] <Preparation of test solution (5-minute dispersion) for evaluation testing of baked paint formulations> The aqueous coating compositions obtained in Examples 45-64 and Comparative Examples 25-28 as described above were dispersed at 2000 rpm for 5 minutes using a disperser equipped with a φ5 cm cowless blade (pre-high shear step). The 5-minute dispersion in this step corresponds to a short-time high shear step.

[0227] <Preparation of water-based paint compositions containing baking paint: for 20-minute dispersions> 100 parts of the baking paints shown in Table 13 were weighed into a 300 mL tall glass beaker. To this, 1 part each of the defoaming agents E9, E11-13, E15, E18, E24, E27, E32, E33, E45-E54, and C15, C20, C23, and C25, obtained as described above, were added dropwise over 1 minute while stirring at 1000 rpm to obtain the water-based paint compositions (for 20-minute dispersions) of Examples 45-64 and Comparative Examples 25-28 (all in Table 16).

[0228] <Preparation of a test solution (20-minute dispersion) for evaluation testing of baked paint formulations> The water-based paint compositions obtained in Examples 45-64 and Comparative Examples 25-28 as described above were dispersed at 2000 rpm for 20 minutes using a disperser equipped with a φ5 cm cowless blade (pre-high shear process). The 20-minute dispersion in this process is equivalent to a long-duration high shear process. Test solutions with a high specific gravity recovery rate after 20 minutes of dispersion are considered to have superior shear resistance.

[0229] The dispersions (5-minute dispersions and 20-minute dispersions) of Examples 1-64 and Comparative Examples 1-28 obtained in the above pre-shearing process were transferred to 200 mL poly cups, degassed for 2 minutes in degassing mode using Awatori Rentaro ARE-310 (manufactured by Thinky Co., Ltd.), and allowed to stand at room temperature for 2 hours or more before being used as the test solutions for the Examples and Comparative Examples (degassing process).

[0230] [Evaluation Method] The aqueous coating compositions obtained as described above, Examples 1 to 64 and Comparative Examples 1 to 28, were evaluated as follows.

[0231] (Evaluation of shear resistance) The test solution obtained in the degassing process was transferred to 100 200 mL poly cups and dispersed at 2000 rpm for 5 minutes using a disperser equipped with a clover blade to induce foaming (foaming process). In this process, dispersion refers to the foaming process. The reason for separating the prior high-shearing process and the foaming process is to ensure that the conditions in the foaming process are the same.

[0232] <Evaluation of air-drying paint formulations> The specific gravity of the test solution was measured using a specific gravity cup immediately after foaming, and again 1 minute and 5 minutes later. The specific gravity recovery rate was calculated as the percentage relative to the specific gravity of the test solution before foaming. A specific gravity recovery rate closer to 100% indicates superior defoaming performance. The 1 minute and 5 minutes used in calculating the specific gravity recovery rate both represent the time required for specific gravity recovery. The specific gravity recovery rate at 1 minute was evaluated primarily as an indicator related to foam suppression, while the specific gravity recovery rate at 5 minutes was evaluated primarily as an indicator related to foam breaking. Specific gravity recovery rate (after 1 minute) = (Specific gravity of the test solution from immediately after foaming to 1 minute later) / (Specific gravity of the test solution before foaming) × 100 [%] Specific gravity recovery rate (after 5 minutes) = (Specific gravity of the test solution from immediately after foaming to 5 minutes later) / (Specific gravity of the test solution before foaming) × 100 [%]

[0233] Shear resistance was evaluated according to the following criteria. It was determined that the material possessed the shear resistance required by the present invention if both the specific gravity recovery rate (1 minute) and the specific gravity recovery rate (5 minutes) in the test solution dispersed for 5 minutes were rated C or higher, and at least one of the specific gravity recovery rates (1 minute) and the specific gravity recovery rate (5 minutes) in the test solution dispersed for 20 minutes was rated C or higher. <Evaluation criteria for specific gravity recovery rate (1 minute)> Specific gravity recovery rate (1 minute) [%] of 95% or higher: Excellent (A) Specific gravity recovery rate (1 minute) [%] is 85% or more and less than 95%: Excellent (B) Specific gravity recovery rate (1 minute) [%] is 75% or more but less than 85%: Effectiveness is observed (C) Specific gravity recovery rate (1 min) [%] less than 75%: Inferior defoaming effect (D) <Evaluation criteria for specific gravity recovery rate (5 minutes)> Specific gravity recovery rate (5 minutes) [%] of 98% or higher: Excellent (A) Specific gravity recovery rate (5 minutes) [%] is 90% or more but less than 98%: Excellent (B) Specific gravity recovery rate (5 minutes) [%] is 80% or more but less than 90%: Effectiveness is observed (C) Specific gravity recovery rate (5 minutes) [%] is less than 80%: Inferior defoaming effect (D)

[0234] <Evaluation of baking paint formulations> Immediately after foaming, the specific gravities of the test solutions at 1 minute and 5 minutes later were measured using a specific gravity cup, and the percentage with respect to the specific gravity of the same test solution before foaming was calculated as the specific gravity recovery rate. The closer the specific gravity recovery rate is to 100%, the better the defoaming property. The times of 1 minute and 5 minutes when calculating the specific gravity recovery rate are both the times required for specific gravity recovery. The specific gravity recovery rate at 1 minute was evaluated mainly as an index related to foam suppression property, and the specific gravity recovery rate at 5 minutes was evaluated mainly as an index related to foam breaking property. Specific gravity recovery rate (after 1 minute) = (Specific gravity of the test solution 1 minute after foaming) / (Specific gravity of the test solution before foaming) × 100 [%] Specific gravity recovery rate (after 5 minutes) = (Specific gravity of the test solution 5 minutes after foaming) / (Specific gravity of the test solution before foaming) × 100 [%]

[0235] The shear resistance was evaluated according to the following criteria. In the test solution dispersed for 5 minutes, when both the specific gravity recovery rate (1 minute) and the specific gravity recovery rate (5 minutes) are C evaluation or higher, and in the test solution dispersed for 20 minutes, at least one of the specific gravity recovery rate (1 minute) and the specific gravity recovery rate (5 minutes) is C evaluation or higher, it was determined that it has the shear resistance required in the present invention. <Evaluation criteria for specific gravity recovery rate (1 minute)> Specific gravity recovery rate (1 minute) [%] is 99.5% or more: Extremely excellent (A) Specific gravity recovery rate (1 minute) [%] is 95% or more and less than 99.5%: Excellent (B) Specific gravity recovery rate (1 minute) [%] is 90% or more and less than 95%: Effect is recognized (C) Specific gravity recovery rate (1 minute) [%] is less than 90%: Inferior in defoaming effect (D) <Evaluation criteria for specific gravity recovery rate (5 minutes)> Specific gravity recovery rate (5 minutes) [%] is 99.5% or more: Extremely excellent (A) Specific gravity recovery rate (5 minutes) [%] is 95% or more and less than 99.5%: Excellent (B) Specific gravity recovery rate (5 minutes) [%] is 90% or more and less than 95%: Effect is recognized (C) Specific gravity recovery rate (5 minutes) [%] is less than 90%: Inferior in defoaming effect (D)

[0236] Furthermore, because the foaming properties and specific gravity of the paint itself (blank) without added defoaming agent differ depending on the paint formulation, the evaluation criteria for shear resistance in baked paint formulations using ACD-2001 differ from the evaluation criteria for shear resistance in air-drying paint formulations using AP-3900.

[0237] (Evaluation of painted appearance) The appearance of the coating film was evaluated after applying the test solution (with an air-drying paint formulation) to a glass plate, followed by drying and baking.

[0238] <Evaluation of air-drying paint formulations> The test solution obtained in the degassing process was applied to a glass plate using a bar coater #42, dried at room temperature for one day, and the appearance of the coating film was evaluated. The appearance of the coating was evaluated according to the following criteria. ○: No fish-eye-shaped repellency is observed on the coating. ○ - : Three or fewer dents are observed on the paint film. △: Three or fewer fish-eye shaped spots are visible on the coating. ×: More than three fish-eye-shaped spots or significant blemishes are visible on the coating.

[0239] <Evaluation of baking paint formulations> The test solution obtained in the degassing process was applied to a glass plate using a 200 μm applicator. The film was then formed under the following conditions: setting: room temperature for 5 minutes, preheating: 80°C for 5 minutes, and baking: 140°C for 30 minutes. The appearance of the coating was then evaluated. The appearance of the coating was evaluated according to the following criteria. ○: No fish-eye-shaped repellency is observed on the coating. ○ - : Three or fewer dents are observed on the paint film. △: Three or fewer fish-eye shaped spots are visible on the coating. ×: More than three fish-eye-shaped spots or significant blemishes are visible on the coating.

[0240] (Evaluation of topcoatability) The risk of topcoat inhibition was determined based on whether or not the water-based paint composition contained a silicone compound ("Presence or absence of silicone"). No risk of silicone-induced interference with topcoats: None (does not contain silicone compounds) Risk of silicone-induced interference with topcoats: Yes (including silicone compounds)

[0241] [Evaluation Results] Tables 14 to 16 show the results of the performance evaluation as described above. For the Blank sample (sample without defoaming agent), the specific gravity recovery rate (1 minute) and specific gravity recovery rate (5 minutes) data listed in the "5-minute dispersion" column of Tables 15 and 16 are the results of foaming a sample that had not undergone the pre-shear process and then checking its specific gravity. Furthermore, when a 20-minute pre-shear process was performed on the Blank sample, the foaming during the pre-shear process was so significant that the shear resistance evaluation test was discontinued.

[0242] [Table 14]

[0243] [Table 15]

[0244] [Table 16]

[0245] The water-based paint compositions in Examples 1 to 64 possessed the performance required by the present invention in terms of shear resistance, paint appearance, and topcoatability.

[0246] From a comparison of Examples 1, 9, 12, and 16, it can be seen that when the HLB of nonionic surfactant (A) is 2 or higher, the painted appearance tends to be particularly excellent.

[0247] Comparisons of Examples 1, 20, and 23 show that polymer (B) exhibits particularly excellent shear resistance when its SP value is 9.5 or less.

[0248] Comparisons of Examples 1, 21, 27, and 31 show that when the weight-average molecular weight of polymer (B) is 300,000 or less, it exhibits particularly excellent shear resistance and paint appearance.

[0249] Comparisons of Examples 1, 34, 36, and 38 show that when the aspect ratio of organic solid particles (C) is within the range of 2.0 to 11, the shear resistance is particularly excellent.

[0250] On the other hand, Comparative Examples 1-3 and 25, which did not contain organic solid particles (C) as an antifoaming agent component, and Comparative Examples 4-6, which did not contain nonionic surfactant (A) and polymer (B), all exhibited inferior shear resistance. In addition, separation of the antifoaming agent occurred in the water-based paint composition of Comparative Example 3. Comparative Example 25 is an example in which organic solid particles (C) were replaced with Merveille 30.

[0251] Furthermore, Comparative Examples 7, 17, and 19, which contained silicone compounds as defoaming agents, and Comparative Examples 8, 20-24, which contained hydrophobic silica, exhibited inferior paint appearance. In addition, Comparative Examples 7, 17, and 19, which contained silicone compounds, also carried the risk of topcoat inhibition due to the presence of the silicone compounds.

[0252] Furthermore, in Comparative Examples 9-14, which included nonionic surfactants with an HLB of more than 16 (non-A component), the defoaming agent compositions (defoaming agent samples) separated, and further testing was discontinued.

[0253] Furthermore, Comparative Examples 15 to 19, which included polymers other than polymer (B) of the present invention (non-B component) as the polymer, were inferior in at least one of shear resistance or paint appearance. In particular, Comparative Examples 17 and 19, which included a silicone compound as the polymer, were excellent in shear resistance but inferior in paint appearance.

[0254] Furthermore, comparative examples 20-24, which included inorganic solid fine particles (non-C component) as solid fine particles, exhibited excellent shear resistance but inferior paint appearance.

Claims

1. A defoaming agent composition for water-based paints, A nonionic surfactant (A) having at least one hydrophilic portion selected from the group consisting of an ethylene glycol portion, a polyethylene glycol portion, and a polyhydric alcohol portion, and having an HLB of 1 to 16, A polymer (B) that does not have the aforementioned hydrophilic portion in its molecule, has an SP value of 7.5 to 12, and a weight-average molecular weight of 400 to 1,000,000, Organic solid fine particles (C) in a solid state in the defoaming agent composition at 25°C, An antifoaming agent composition characterized by containing the following:

2. The defoaming agent composition according to claim 1, characterized in that the nonionic surfactant (A) is one or more selected from the group consisting of ethylene glycol aliphatic ether, polyoxyalkylene aliphatic ether, polyoxyalkylene aromatic ether, polyoxyalkylene fatty acid ester, alkylene oxide addition derivative of castor oil, alkylene oxide addition derivative of hydrogenated castor oil, polyoxyalkylene polyhydric alcohol ether, polyhydric alcohol fatty acid ester, alkylene oxide addition derivative of polyhydric alcohol fatty acid ester, polyoxyalkylene alkylamide, acetylene glycol and its derivatives, alkylene oxide addition derivative of acetylene glycol, polyoxyethylene-polyoxypropylene block copolymer, and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer.

3. The defoaming agent composition according to claim 1, characterized in that the polymer (B) is one or more polymers selected from the group consisting of polyvinyl alkyl ether, polybutadiene, polybutene, polyisoprene, polyalphaolefin, polyalkyl (meth)acrylate, copolymer of dibasic acid ester, polyfatty acid vinyl ester, copolymer of alkyl (meth)acrylate and fatty acid vinyl ester, and polyalkylene glycol derivative (provided that the polyalkylene glycol derivative does not have the ethylene glycol portion, the polyethylene glycol portion, and the polyhydric alcohol portion, and the weight-average molecular weight of the polyalkylene glycol derivative is 400 to 1,000,000).

4. The defoaming agent composition according to claim 1, characterized in that the organic solid fine particles (C) are one or more solid fine particles selected from the group consisting of amides, ureas, polyethylene, oxidized polyethylene, acid-modified polyethylene, and hydrogenated castor oil.

5. The defoaming agent composition according to claim 4, characterized in that the amide is a fatty acid diamide obtained by reacting fatty acids selected from the group consisting of alkyl fatty acids and hydroxy fatty acids, including at least one hydroxy fatty acid, with diamines including one or more diamines selected from the group consisting of alkylenediamines having 2 to 6 carbon atoms and m-xylylenediamine.

6. The defoaming agent composition according to claim 1, characterized in that the aspect ratio of the crystals of the organic solid fine particles (C) is 1.1 to 100.

7. The molecule does not contain the aforementioned hydrophilic portion and further contains an organic medium (D) other than water that is liquid at 25°C. The defoaming agent composition according to claim 1, characterized in that the weight-average molecular weight of the organic medium (D) is less than 400.

8. The defoaming agent composition according to claim 7, characterized in that the organic medium (D) is one or more selected from the group consisting of hydrocarbon oils, alcohols, glycol ethers, and glycol esters.

9. The defoaming agent composition according to claim 1, characterized in that it does not contain a silicone compound.

10. A water-based paint composition characterized by comprising the defoaming agent composition according to any one of claims 1 to 9 and a water-based resin.

11. An article coated with a coating agent comprising the defoaming agent composition according to any one of claims 1 to 9.

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