Water-soluble silicone defoamer composition and water-based paint containing same

Abstract

[Problem] To provide: a water-soluble silicone anti-foaming agent composition which can exhibit uniform solubilization with an aqueous phase, meets the WHO-defined property of being free of volatile organic compounds (VOC), and exhibits excellent anti-foaming characteristics and storage stability; and an aqueous coating material additive and aqueous coating material using same. [Solution] A water-soluble silicone anti-foaming agent composition that contains: (A) a polyether-modified silicone or polyglycerol-modified silicone having an average HLB value within the range 0.5-5.0, or a mixture of these; (B) at least one selected from between triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether; and (C) water.

Description

[Technical field]

[0001] The present invention relates to a water-soluble silicone defoamer composition and a water-based paint containing the same. The present invention also relates to a method for defoaming water-based paint and a method for maintaining quality, which are characterized by the addition of the water-soluble silicone defoamer composition. [Background technology]

[0002] Conventionally, silicone-based defoamers exert defoaming effects with the addition of small amounts compared to non-silicone defoamers such as alcohol-based, ester-based, mineral oil, vegetable oil, and synthetic oil, and are widely used as defoamers and foam suppressors in the fields of chemical industry, food industry, petroleum industry, textile industry, plastics industry, cement industry, paint and adhesive industry, and various compositions have been proposed. In particular, silicone-based defoamers with polyether-modified silicones such as polyoxyalkylene-modified groups and optionally added polypropylene glycol, etc., are liquid and have excellent dispersibility in water, so that the undiluted solution can be used as is or dispersed (diluted) in water and added / blended to a foaming liquid to effectively suppress foaming, and therefore have excellent handling workability and initial defoaming effect, and are widely used industrially (e.g., Patent Documents 1 to 5).

[0003] However, even though these silicone-based defoaming agents are water-dispersible, they are not uniformly solubilized in the water phase, and they cause the suspension of the water phase and the decrease in transparency, so that their use is limited.In addition, Patent Document 6 proposes adding water-soluble polymers such as polyether-modified silicone, polyhydric alcohol alkyl ether, and optionally polyvinyl alcohol to silicone-based defoaming agents, but when the components disclosed in this document are used, they only improve water dispersibility and do not lead to solubilization.For this reason, there is a strong demand for a water-soluble silicone defoaming agent composition that can be uniformly solubilized in the water phase and has excellent defoaming properties and storage stability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Publication No. 3,233,986 [Patent Document 2] Japanese Patent Application Publication No. 54-149388 [Patent Document 3] Japanese Patent Application Publication No. 56-48211 [Patent Document 4] Japanese Patent Application Laid-Open No. 63-147507 [Patent Document 5] Japanese Patent Application Publication No. 07-185212 [Patent Document 6] JP 2000-246009 A Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to the above problems, the present applicant has discovered a new problem related to the present invention. In silicone-based defoamers, low molecular weight alcohols such as isopropanol (IPA) are widely used as a dispersion medium for the purpose of improving the dispersibility in water and storage stability. In recent years, the World Health Organization (WHO) and other organizations have strongly demanded industrial products that emit less low-boiling or volatile organic compounds, so-called Volatile Organic Compounds (VOCs), into the environment. However, IPA, which has a boiling point of 82°C, is a volatile organic compound (VOC, boiling point 50 to 260°C) as defined by the WHO, and is also a highly volatile organic compound, Very Volatile Organic Compounds (VVOC, boiling point 100°C or less), so its use is not preferred from the viewpoint of reducing environmental load / eco-friendliness. However, alcohols that can be used as a dispersion medium for silicone-based defoamers are VOCs or VVOCs, including IPA, and no silicone-based defoamers that have excellent solubilization properties in water and do not substantially require the use of these dispersion media have been known to date, making it impossible to provide a silicone-based defoamer product with little environmental impact.

[0006] Furthermore, the present applicant has found a new problem in accordance with the present invention. In addition to its storage stability, silicone-based defoamers are generally manufactured by adding preservatives, bactericides, and antibacterial agents to industrial products such as water-based paints, foods, cosmetics, etc., in order to suppress the generation of live bacteria and maintain the quality control and safety of the products. However, some preservatives and bactericides have highly toxic components, and industrial products that use less of them or are preservative / bactericide-free are required. On the other hand, no silicone-based defoamers that do not substantially require the use of preservatives / bactericides and have excellent solubilization properties in water have been known so far, and it has not been possible to provide such preservative / bactericide-free silicone-based defoamer products.

[0007] That is, the object of the present invention is to provide a water-soluble silicone antifoaming composition that can be uniformly solubilized in an aqueous phase, is free of volatile organic compounds (VOCs) as defined by the WHO, and has excellent antifoaming properties and storage stability.Furthermore, the object of the present invention is to provide a water-soluble silicone antifoaming composition that, if necessary, is free of preservatives / bactericides, does not impair storage stability and quality, and is unlikely to cause problems with live bacteria even when incorporated into water-based paints, etc.

[0008] Similarly, an object of the present invention is to provide a water-based paint additive and a water-based paint which use the above-mentioned water-soluble silicone defoamer composition, and to provide a method for defoaming water-based paint and a method for preserving quality, which are characterized by the addition of the water-soluble silicone defoamer composition. [Means for solving the problem]

[0009] As a result of intensive research conducted by the inventors in order to solve the above-mentioned problems, they discovered that the above-mentioned problems can be solved by a water-soluble silicone defoamer composition that uses in combination with a polyether-modified silicone having an average HLB value within a specific range, one or more types selected from triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether, and water, and thus arrived at the present invention.

[0010] In detail, the water-soluble silicone antifoaming agent composition of the present invention contains (A) one or more kinds of polyether-modified silicones, polyglycerin-modified silicones or mixtures thereof, (B) one or more kinds selected from triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether, and (C) water. Here, the above-mentioned component (B), particularly preferably triethylene glycol mono-n-butyl ether, is a component that can realize specific water solubility when used in combination with the components (A) and (C), and has a boiling point of 260°C or higher, so it does not fall under the VOC defined by WHO, and a VOC-free composition can be designed as needed. In addition, by using the above-mentioned (B) component, the proliferation of live bacteria in the composition is strongly suppressed, and a preservative / bactericide-free silicone antifoaming agent composition and a water-based paint containing it can be designed as needed. It should be noted that the technical effect cannot be achieved with other triethylene glycol alkyl ethers of similar structure. Effect of the Invention

[0011] The water-soluble silicone defoamer composition of the present invention has sufficient defoaming properties and storage stability for practical use, can be uniformly solubilized in water phase, and does not cause problems of turbidity or phase separation.Furthermore, the water-soluble silicone defoamer composition of the present invention can achieve the volatile organic compound (VOC)-free definition of WHO, and can provide a water-soluble silicone defoamer composition and water-based paint that are free of preservatives / bactericides as necessary.

[0012] Furthermore, the water-soluble silicone defoamer composition of the present invention can provide a water-based paint additive and a water-based paint, and can also provide a method for defoaming water-based paint and a method for preserving quality, which are characterized by the addition of the water-soluble silicone defoamer composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The water-soluble silicone antifoaming agent composition of the present invention will be described. The composition contains (A) one or more polyether-modified silicones, polyglycerin-modified silicones or mixtures thereof having an average HLB value in the range of 0.5 to 5.0, (B) one or more selected from triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether, and (C) water, and may optionally further contain (D) one or more nonionic surfactants having an average HLB value of 2.0 to 12.0 (excluding component (A)), (E) hydrophobic silica, (F) organopolysiloxane having a silanol group at the molecular chain end, (G) polypropylene glycol, etc. The "HLB value" in the water-soluble silicone antifoaming agent composition of the present invention is a calculated value given by Griffin's formula based on the molecular structure of the target.

[0014] [Component (A)] Component (A) of the present invention is one or more types of polyether-modified silicones, polyglycerin-modified silicones, or mixtures of these, all having an average HLB value in the range of 0.5 to 5.0, and is an essential component for solubilizing in water defoaming components such as the defoaming compound containing hydrophobic silica and / or organopolysiloxane having silanol groups at the molecular chain terminals described below, when used in combination with components (B) and (C).

[0015] Component (A) is a silicone compound having at least one polyether modified group, typically a polyoxyalkylene group, or a polyglycerin modified group having two or more glycerol units in the molecule, and examples thereof include one or more selected from polyether modified silicones, polyglycerin modified silicones, polyether-polyglycerin co-modified silicones, and mixtures thereof. The structure of the silicone compound is not particularly limited, and may be a linear, branched, resinous, or cyclic polysiloxane structure, or may have a block copolymer or crosslinked polysiloxane structure, including a structure in which two or more polysiloxane structures are linked or crosslinked by a polyoxyalkylene structure or an alkylene structure. Here, the crosslinked polysiloxane structure is exemplified by an organopolysiloxane having a partially crosslinked structure in which a plurality of linear organopolysiloxanes are crosslinked. From the standpoint of water solubilization, component (A) is preferably a linear or branched polydimethylsiloxane having a polyether-modified group or a polyglycerin-modified group on the side chain or at the end, and may optionally have a long-chain alkyl group such as a decyl group or a halogenated alkyl group such as a fluoroalkyl group in the molecule.

[0016] Component (A) is preferably a polyether-modified silicone having a polyoxyalkylene group in the molecule, -R 1 -O(C 2 H 4 O) p (C 3 H 6 O) q -R 2 (where R 1 is a divalent hydrocarbon group having 1 to 4 carbon atoms, R 2 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and p and q are integers satisfying 10≦p+q≦100 and 10:90≦p:q≦100:0). 2 H 4 O unit is "EO", C 3 H 6 The O unit is sometimes called "PO". 1The divalent hydrocarbon group having 1 to 4 carbon atoms includes a methylene group, an ethylene group, a propylene group, and a butylene group. 2 Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

[0017] From the viewpoint of water solubility, it is necessary that the average HLB value of component (A) is in the range of 0.5 to 5.0. Here, the average HLB value means that if component (A) is one type of polyether-modified silicone, etc., its HLB value is in the range of 0.5 to 5.0, but if component (A) is a mixture of two or more types of polyether-modified silicone, etc., it means that the average value of the HLB values ​​of the individual polyether-modified silicone, etc. according to their mass ratio is in the range of 0.5 to 5.0. In other words, when component (A) is a mixture of two or more types of polyether-modified silicone, etc., each polyether-modified silicone, etc. may have an HLB value of less than 0.5 or more than 5.0.

[0018] Particularly preferably, component (A) is (A1) a polyether-modified silicone or a mixture thereof having an average HLB value in the range of 1.0 to 4.0, and particularly preferably an average HLB value in the range of 1.0 to 3.0, 1.1 to 2.5, or 1.2 to 2.0.

[0019] As long as the above-mentioned condition for the average HLB value is satisfied, there are no particular limitations on the molecular weight and viscosity (25°C) of component (A); from the standpoint of handling and blend stability in the water-soluble silicone defoamer composition, it is preferable for the kinetic viscosity at 25°C to be in the range of 5 to 10,000 mPa s, and particularly preferably in the range of 100 to 5000 mPa s.

[0020] [Component (B)] The component (B) of the present invention is one or more selected from triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether, and is preferably triethylene glycol mono-n-butyl ether (sometimes called "butoxy triglycol" or "butyl triglycol" as a trade name). The component (B) is a component that can achieve the solubilization of the silicone defoamer composition of the present invention in water by using it in combination with the above-mentioned component (A) and the water component (C), and since its boiling point is 260°C or higher, it does not fall under the VOC defined by WHO, and if necessary, a VOC-free composition can be designed for the composition of the present invention. Note that, since the technical effect cannot be achieved with other triethylene glycol alkyl ethers of similar structure, it is necessary to use at least one of the above two types, preferably triethylene glycol mono-n-butyl ether.

[0021] The applicant also discovered that the use of one or more of triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether strongly inhibits the proliferation of live bacteria in the silicone defoamer composition itself and in water-based paints containing said composition, making it possible to design a preservative / bactericide-free composition. Similar effects, particularly effects comparable to those of commonly used preservatives, have not been confirmed with other dispersion media.

[0022] [Component (C)] Component (C) of the present invention is water, which is a component that forms an aqueous phase in which the defoaming components such as the defoaming compound made of organopolysiloxane of the composition, any nonionic surfactant, and any water-soluble optional components such as polypropylene glycol are dispersed, and which is a component that can achieve solubilization of the entire silicone defoamer composition of the present invention in water by using it in combination with the above-mentioned components (A) and (B). Note that the water may previously contain other water-soluble optional components described later.

[0023] The water is clean and preferably does not contain any components that inhibit the storage stability of the silicone antifoam composition of the present invention, and examples of such water include ion-exchanged water, distilled water, well water, and tap water. From the standpoint of designing a preservative / bactericide-free composition, it is practically preferable for the water to be clean water in which the proliferation of bacteria has been suppressed by ozonation, heating, filtration, or the like.

[0024] The silicone antifoam agent composition of the present invention essentially comprises the above-mentioned components (A) to (C), and when the entire composition is taken as 100 mass %, The content of the component (A) is preferably in the range of 1 to 70% by mass, more preferably in the range of 5 to 50% by mass, and particularly preferably in the range of 5 to 30% by mass. The content of the component (B) is preferably in the range of 1 to 50% by mass, more preferably in the range of 5 to 50% by mass, and particularly preferably in the range of 5 to 30% by mass. The content of the component (C) is preferably in the range of 1 to 70 mass %, more preferably in the range of 5 to 60 mass %, and particularly preferably in the range of 5 to 50 mass %. The silicone antifoam agent composition of the present invention preferably contains an optional component other than components (A) to (C).

[0025] [Component (D)] The component (D) of the present invention is one or more kinds of nonionic surfactants having an average HLB value of 2.0 to 12.0, and the component (A) is excluded from this range. The use of the component (D) in combination with the component (A) has the advantage that the uniformity and storage stability of the entire composition are further improved, and the solubilization and dispersibility in water are further improved. On the other hand, if the average HLB value of the nonionic surfactant is less than the lower limit, the solubilization in water may not be sufficiently improved. If the average HLB value exceeds the upper limit, the solubilization in water and the uniformity of the entire composition may be impaired depending on the combination of the silica component and the organopolysiloxane component described below. Note that the component (D) may contain a silicone-based nonionic surfactant such as polyoxyalkylene-modified silicone, polyglyceryl-modified silicone, glyceryl-modified silicone, or sugar-modified silicone, as long as it has an average HLB value different from that of the component (A). However, from the viewpoint of improving the water solubilization, it is particularly preferable that the nonionic surfactant is an organic compound that does not contain a siloxane bond in the molecule. The average HLB value of the component (D) is preferably 11 or less, and more preferably in the range of 5-11, or 6-10.

[0026] Examples of the nonionic surfactants that are component (D) include polyoxyalkylene ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters (e.g., those composed of polyethylene glycol (or ethylene oxide) and higher fatty acids (e.g., linear or branched fatty acids having 12 to 18 carbon atoms)), polyoxyalkylene fatty acid diesters, polyoxyalkylene resin acid esters, polyoxyalkylene (hydrogenated) castor oils, polyoxyalkylene alkylphenols, polyoxyalkylene alkyl phenyl ethers, polyoxyalkylene phenyl ethers, polyoxyalkylene alkyl esters, polyoxyalkylene alkyl esters, sorbitan fatty acid esters, and the like. Examples of the fatty acid esters include polyoxyalkylene sorbitan alkyl esters (for example, those composed of sorbitan, polyethylene glycol, and higher fatty acids (for example, linear or branched fatty acids having 12 to 18 carbon atoms)), polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene glycerin fatty acid esters, polyglycerin alkyl ethers, polyglycerin fatty acid esters, sucrose fatty acid esters, fatty acid alkanolamides, alkyl glucosides, polyoxyalkylene fatty acid bisphenyl ethers, polyoxyethylene-polyoxypropylene block polymers, and alkyl polyoxyethylene-polyoxypropylene block polymer ethers.

[0027] From the viewpoint of water solubility, component (D) is preferably (D1) a polyoxyalkylene monoalkyl ether or a mixture thereof having an average HLB value of 11 or less, and the average HLB value may be in the range of 5 to 11, or 6 to 10.

[0028] [Component (E)] Component (E) is hydrophobic silica, and together with component (F), it is a component that imparts defoaming properties and defoaming persistence, and specific examples include hydrophobically treated fumed silica, calcined silica fine powder, precipitated silica fine powder, silica aerogel, quartz fine powder, and fused silica fine powder. In terms of the defoaming effect, these hydrophobic silicas preferably have a BET specific surface area of ​​50 m2 / g or more, and particularly preferably 100 m2 / g or more.

[0029] The hydrophobization treatment of component (E) is not particularly limited, but it is common to knead it with a hydrophobizing agent such as component (F), organosilane, or organosiloxane oligomer to hydrophobize the surface. Well-known compounds can be used as organosilanes or organosiloxane oligomers, and examples of organosilanes include dimethyldichlorosilane, methyltrichlorosilane, hexamethyldisilazane, and dimethyldialkoxysilane. Examples of organosiloxane oligomers include dimethylsiloxane oligomers with both ends blocked by silanol groups, methylhydrogensiloxane oligomers with both ends blocked by trimethylsiloxy groups, 1,1,3,3-tetramethyldisiloxane, and 1,3,5,7-tetramethylcyclotetrasiloxane. Other examples of hydrophobizing agents include stearic acid, sodium stearate, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(N-2-aminoethyl)aminopropyltrimethoxysilane.

[0030] [Component (F)] Component (F) is an organopolysiloxane having silanol groups at the molecular chain terminals, and can form a silicone compound that imparts defoaming properties and defoaming persistence to the composition by mixing it with itself or with component (E).

[0031] From the viewpoint of the defoaming property and water-solubilizing property of the composition, component (F) is preferably a dimethylpolysiloxane having silanol groups at both molecular chain terminals, and may further contain a hydrophobic functional group such as fluoroalkyl, if desired. The kinetic viscosity of component (F) at 25°C is not particularly limited, but may be in the range of 1.5 to 100,000 mPa·s, preferably in the range of 5.0 to 10,000 mPa·s, and more preferably in the range of 5.0 to 5,000 mPa·s. In particular, a preferred example of component (F) of the present invention is (F1), a dimethylpolysiloxane having silanol groups at both molecular chain terminals, whose viscosity at 25°C is in the range of 5.0 to 1,000 mPa·s.

[0032] When the component (E) and the component (F) are used in combination to form an antifoaming silicone compound, the mass ratio of the component (F) to the component (E) is preferably in the range of 100:1 to 50. If the mass ratio of the hydrophobic silica component (F) is less than 1, the expected antifoaming properties and antifoaming persistence may not be realized, while if the mass ratio of the component (F) exceeds 50, it may be difficult to prepare a uniform antifoaming composition. From the viewpoint of antifoaming properties, it goes without saying that only the component (E) or the component (F) may be used alone.

[0033] [Component (G)] Component (G) is polypropylene glycol, and is preferably used in combination with the above components (A) to (E) to improve the defoaming properties and defoaming persistence of the entire silicone defoaming agent composition according to the present invention. In particular, by using component (A) as triethylene glycol mono-n-butyl ether and polypropylene glycol as component (G) in combination, a silicone defoaming agent composition having excellent uniformity and water-solubilizing properties, and further improved defoaming properties and defoaming persistence can be obtained.

[0034] The above components (D) to (G) are optional components of the present invention, and when the entire composition is taken as 100 mass %, The content of the component (D) is preferably in the range of 0 to 40% by mass, more preferably in the range of 5 to 40% by mass, and particularly preferably in the range of 5 to 35% by mass. The content of the component (E) is preferably in the range of 0 to 5 mass %, more preferably in the range of 0.1 to 3 mass %, and particularly preferably in the range of 0.2 to 2 mass %. The content of the component (F) is preferably in the range of 0 to 10 mass %, more preferably in the range of 0.2 to 8 mass %, and particularly preferably in the range of 0.5 to 6 mass %. The content of the component (G) is preferably in the range of 0 to 50% by mass, more preferably in the range of 0 to 30% by mass, and particularly preferably in the range of 5 to 25% by mass.

[0035] [Other optional ingredients] The silicone defoaming composition of the present invention may contain other emulsifiers, alcohols, solvents, stabilizers, thickeners, preservatives, pH adjusters, etc., within the scope of not impairing the object of the present invention. The amount of the defoaming composition of the present invention to be added to the target object when used is determined depending on various conditions such as the target process, the properties of the target object to be defoamed, and the effect on the physical properties of the final product, but as a general guideline, it is desirable to add 1 to 500 ppm in the case of a high-concentration defoaming composition containing a small amount of water, and 100 to 10,000 ppm in the case of a low-concentration defoaming composition containing a large amount of water.

[0036] On the other hand, in the silicone defoamer composition of the present invention, by selecting component (B), it is possible to achieve the VOC-free defined by WHO, and also to achieve preservative / bactericide-free. Therefore, when having these technical intentions, it is particularly preferable not to use low-boiling alcohols or solvents, and not to use preservatives, etc. For example, in the case of preservative / bactericide-free, the content of preservative or bactericide component is 0.05 mass% or less of the entire water-based paint containing the silicone defoamer composition, and it is particularly preferable that it does not substantially contain preservatives and bactericides.

[0037] [Manufacturing method] The silicone antifoaming agent composition of the present invention can be produced by uniformly stirring the above components (A) to (C) and other components using mechanical force such as a mixer. There are no particular limitations on the stirring / mixing device as long as it is capable of charging the raw materials and uniformly stirring them, and there are no particular limitations on the temperature conditions during stirring as long as it is capable of uniform stirring. Heating up to about 50°C may be used for the purpose of reducing viscosity, etc. The above components (E) and (F) may be mixed in advance and blended in the form of a silicone compound, or a water-soluble component may be mixed in advance in water, which is component (C), and then the whole may be uniformly stirred. Furthermore, if necessary, after uniformly stirring each component, it may be further treated with a high-pressure emulsifying device capable of applying high shear force, such as a colloid mill, a ball mill, a disper mill, a homogenizer, or a Gaulin homogenizer.

[0038] [Application] The water-soluble silicone defoamer composition of the present invention is effective against aqueous foaming liquids and can be particularly suitably used as a defoamer for paints (water-based paints, paper coating paints, etc.) and various manufacturing processes (papermaking processes, fermentation processes, wastewater treatment processes, monomer stripping processes, polymer polymerization processes, etc.), and by being solubilized in the aqueous phase, it can achieve excellent defoaming or foam suppressing effects while maintaining a transparent to semi-transparent and uniform appearance.

[0039] In particular, the water-soluble silicone defoamer composition of the present invention is suitable as an additive for water-based paints, and is also suitable as a defoamer for water-based paints.Among water-based paints (water-based architectural exterior paints, architectural interior paints, water-based inks, and paper coating paints, etc.), it is particularly suitable as a defoamer for emulsion-containing water-based paints and paper coating paints.The emulsions used in emulsion paints include emulsions of vinyl acetate resins, acrylic resins, styrene resins, halogenated olefin resins, urethane resins, silicone resins, or fluorine atom-containing silicone resins, and are effective for all of them, and are particularly effective for acrylic paints containing acrylic resins, acrylic styrene paints, acrylic urethane paints, and acrylic silicone paints. Furthermore, the water-soluble silicone defoamer composition of the present invention is uniformly solubilized in the aqueous phase, and is therefore effective for all aqueous paints, including alcohol-based or emulsion-type paints; unlike conventional emulsion-type silicone defoamers and suspension-type silicone defoamers, it is uniformly solubilized in the aqueous phase of the paint, and is therefore less likely to affect the formulation or stability of the emulsion, etc., and is capable of achieving high defoaming or foam-suppressing performance.

[0040] When the water-soluble silicone antifoaming agent composition of the present invention is applied to the above-mentioned water-based paint, it may be added during pigment dispersion or after paint preparation, but it is particularly preferable to add it after paint preparation in which the aqueous phase is the continuous layer. When applied to various manufacturing processes, it may be added (1) together with the supply of raw materials, (2) before heating and / or decompression treatment, and / or (3) in the final finishing process, etc.

[0041] The amount of the water-soluble silicone antifoam agent composition of the present invention added is, converted into solid content, in the range of 0.01 to 2.0 mass% relative to the solid content of the water-based paint, more preferably 0.05 to 1.0 mass%, and particularly preferably 0.05 to 0.5 mass%.

[0042] [Methods for defoaming water-based paints and preserving their quality] The water-soluble silicone defoaming agent composition of the present invention can be preferably blended in the above-mentioned amount with water-based paint to realize defoaming or foam suppression effect.Furthermore, as mentioned above, by using component (B), the water-soluble silicone defoaming agent composition of the present invention itself strongly inhibits the proliferation of live bacteria, and can be used for the quality preservation (including antibacterial and putrefaction prevention effects) of water-based paint, and can realize a composition that is substantially free of preservatives / bactericides for the water-based paint. EXAMPLES

[0043] The water-soluble silicone antifoam agent composition of the present invention and the water-based paint containing it will be described in detail with reference to the following examples. The viscosity is measured at 25°C using a rotational viscometer.

[0044] (Appearance and presence or absence of phase separation) The appearance and the presence or absence of phase separation were evaluated visually and rated as "transparent" or "turbid." If even a slight separation was observed, it was rated as "separated", and if the whole was uniform, it was rated as "uniform (no phase separation)".

[0045] (Evaluation of antifoaming: Evaluation based on liquid level after stirring and number of bubbles after 30 seconds) 50g of the coating agent having the following composition was placed in a glass bottle with a diameter of 55mm, and 0.4% by mass of the silicone antifoaming agent of the present invention or other silicone oil was added to prepare a sample. This was stirred for 1 minute at a rotation speed of 5,000 rpm using an edged turbine type stirring blade, and the height of the liquid surface immediately after stirring was stopped was measured to evaluate the antifoaming property (liquid surface height after stirring (mm)). [Table 1] Furthermore, the same sample was painted (20 times back and forth) on a 200mm x 300mm tin-plated steel plate (tinplate) with a medium-pile roller, and the defoaming property (number of bubbles after 30 seconds) was evaluated based on the number of bubbles (diameter 1.0mm or more) within an area of ​​10cm x 15cm in the center after 30 seconds.

[0046] (Flatness / Uniformity of Coating) The above sample was applied to a 150 mm x 50 mm glass plate using a bar coater #16, and the number of cissings occurring within a 10 cm x 10 cm area of ​​the coated surface was visually evaluated. If the number of cissings was 5 or less, it was rated as "good", and if the number was 6 or more, it was rated as "poor", and the number of cissings was recorded.

[0047] (Live bacteria test) The test samples were inoculated with the test bacteria solution prepared after pre-culture, and after a certain period of time, the viable cell count was measured to evaluate the preservative effectiveness. The bacterial species were Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Aspergillus brasiliensis, and Pseudomonas fluorescens. For specimens where uniform samples could not be obtained, viable bacteria tests were not performed.

[0048] In each of the examples and comparative examples, the following components were used. A-1) Polyether-modified silicone with a polyether structure containing EO and PO units in the molecule (HLB 1.6, molecular weight 10,000, viscosity 650 mPa s) A-2) Polyether-modified silicone with a polyether structure containing only EO units in the molecule (HLB 1.8, molecular weight 5000, viscosity 150 mPa s) Among the following B-1) to B-14), only B-1) and B-14) are the component (B) of the present invention used in the examples, and the others are similar compounds and alcohols for comparative experiments. B-1) Triethylene glycol mono-n-butyl ether, purity >98%, manufactured by Tokyo Chemical Industry Co., Ltd. B-2) Diethylene glycol mono-n-butyl ether, purity >98%, Fujifilm Wako Pure Chemical Industries, Ltd. others B-3) 2-Propanol, purity >99.7%, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. B-4) Dipropylene glycol monomethyl ether, purity >95%, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. B-5) Tripropylene glycol monobutyl ether, purity >95%, manufactured by Kanto Chemical Co., Ltd. B-6) Triethylene glycol, purity >98%, manufactured by Alfa Acer B-7) Tetraethylene glycol, purity >95%, manufactured by Tokyo Chemical Industry Co., Ltd. B-8) Tetraethylene glycol dimethyl ether, purity >98%, manufactured by Tokyo Chemical Industry Co., Ltd. B-9) Triethylene glycol dimethyl ether, purity >97%, Fujifilm Wako Pure Chemical Industries, Ltd. B-10) 2-Butoxyethanol / Ethylene glycol mono-n-butyl ether, purity >99%, Fujifilm Wako Pure Chemical Industries, Ltd. B-11) Triethylene glycol dimethyl ether, purity >97%, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. B-12) Triethylene glycol monomethyl ether, purity >98%, manufactured by Tokyo Chemical Industry Co., Ltd. B-13) 2-Ethoxyethyl acetate, purity >98%, manufactured by Kanto Chemical Co., Ltd. B-14) Triethylene glycol butyl methyl ether, purity >97%, Fujifilm Wako Pure Chemical Industries, Ltd. C) Water Ion-exchanged water D-1) Nonionic surfactant: Sanonik SS-30 (manufactured by Sanyo Chemical Industries, Ltd.) HLB=8 D-2) Nonionic surfactant: Sanonic SS-50 (manufactured by Sanyo Chemical Industries, Ltd.) HLB=10.5 E) Hydrophobic silica: Product name: Aerosil R-972 (manufactured by Nippon Aerosil Co., Ltd.) F) Dimethylpolysiloxane with silanol groups at both ends of the molecular chain (molecular weight 900, viscosity 40 mPa s) G) Polypropylene glycol Product name: Sannix PP-2000 (manufactured by Sanyo Chemical Industries, Ltd.)

[0049] [Examples 1 to 4 and Comparative Examples 1 to 2] The above components were uniformly stirred and mixed using a mechanical force (mixer) to the concentration (mass %) shown in Table 1 to prepare a water-solubilized silicone antifoaming agent, which was then allowed to stand for 24 hours and one week, after which the appearance and the presence or absence of phase separation were evaluated using the methods described above and the results are recorded in Table 1. In addition, 0.4 parts by mass (%) was added to an acrylic emulsion paint (U-DOUBLE (registered trademark) E-135, manufactured by Nippon Shokubai Co., Ltd. base), and the mixture was stirred and mixed uniformly using mechanical force (mixer). The defoaming performance, etc. was evaluated using the above method, and the results are shown in the table below.

[0050] [Table 2]

[0051] [Comparative Examples 4 to 13] The B-1) component of "Example 1" in the above table was replaced with components B-4) to B-13), which do not correspond to the component (B) of the present invention, and similarly to Example 1, the components were uniformly stirred and mixed by mechanical force (mixer) to prepare a water-solubilized silicone antifoaming agent, which was then allowed to stand for 24 hours, and the presence or absence of phase separation was determined and recorded by the above method. As a result, in all of the comparative examples using B-4) to B-13), which do not correspond to the component (B) of the present invention, phase separation occurred, and a uniform antifoaming agent composition could not be obtained.

[0052] [Example 5] The B-1) component of "Example 1" in the above table was replaced with component B-14), which is the component (B) of the present invention, and similarly to Example 1, the mixture was uniformly stirred and mixed by mechanical force (mixer) to prepare a water-soluble silicone antifoaming agent, which was then left to stand for 24 hours, and the presence or absence of phase separation was determined and recorded using the above method. As a result, when B-14) triethylene glycol butyl methyl ether was used, the composition was uniformly dispersed and was able to be solubilized in water.

[0053] <Summary> The water-soluble silicone defoamer according to the embodiment is water-soluble, and therefore has excellent handling and uniform dispersibility. When it is simply mixed with a water-based paint by stirring with a mixer, it becomes a uniform and transparent silicone composition, and phase separation does not occur even after one week. Furthermore, the composition has excellent defoaming properties, and not only can a uniform coating film be obtained, but also inhibits the proliferation of live bacteria for a long period of time without the use of preservatives, antibacterial agents, or bactericides, and is antibacterial-free and has excellent storage stability. Furthermore, the component (B) used in the embodiment does not fall under any volatile organic compound, and has the above-mentioned advantages, and realizes a water-soluble silicone defoamer that is free of volatile components (VOCs).

[0054] On the other hand, in the comparative examples that did not use the component (B) of the present invention or used a water-solubilizing agent component other than the component (B), the composition did not disperse in water and phase separated after becoming cloudy, making it difficult to put into practical use. Furthermore, when these compositions were blended into emulsion paints, the defoaming properties were clearly inferior to those of the examples, and the appearance of the coating film was such that it caused coating defects such as cissing. Even when IPA (2-propanol), which corresponds to a volatile component (VOC), was used instead of the component (B) of the present invention, it was not possible to achieve the same technical effect as the present invention (Comparative Example 3).

Claims

1. (A) one or more types of polyether-modified silicones, polyglycerin-modified silicones, or mixtures thereof, each having an average HLB value in the range of 0.5 to 5.0; (B) one or more selected from triethylene glycol mono-n-butyl ether and triethylene glycol butyl methyl ether, (C) water, and (D) A water-soluble silicone defoamer composition containing one or more nonionic surfactants (excluding component (A)) having an average HLB value of 2.0 to 12.

0.

2. 2. The water-soluble silicone defoamer composition of claim 1, further comprising (E) a hydrophobic silica.

3. 3. The water-soluble silicone defoamer composition according to claim 1 or 2, further comprising (F) an organopolysiloxane having silanol groups at the molecular chain terminals.

4. The water-soluble silicone defoamer composition according to any one of claims 1 to 3, further comprising (G) polypropylene glycol.

5. When the entire composition is taken as 100% by mass, The content of the component (A) is in the range of 1 to 70 mass %, The content of the component (B) is in the range of 1 to 50 mass %, The content of the component (C) is in the range of 1 to 70 mass %, The content of the component (D) is in the range of 5 to 40 mass %, The content of the component (E) is in the range of 0 to 5 mass %, The content of the component (F) is in the range of 0 to 10 mass %, and The content of the component (G) is in the range of 0 to 50 mass%. The water-soluble silicone defoamer composition according to any one of claims 1 to 4.

6. The component (A) is (A1) a polyether-modified silicone or a mixture thereof having an average HLB value in the range of 1.0 to 4.0, The water-soluble silicone defoamer composition according to any one of claims 1 to 5, wherein the content of the component (B) is in the range of 10 to 150 parts by mass per 100 parts by mass of the component (A), and the content of the component (C) is in the range of 1 to 200 parts by mass per 100 parts by mass of the component (A).

7. The water-soluble silicone antifoam agent composition according to any one of claims 1 to 6, further comprising (D1) a polyoxyalkylene monoalkyl ether having an average HLB value of 11 or less, or a mixture thereof.

8. The water-soluble silicone defoamer composition according to any one of claims 1 to 7, which is an additive for a water-based paint.

9. A water-based paint comprising the water-soluble silicone defoamer composition according to any one of claims 1 to 7.

10. The water-based paint according to claim 9, further comprising a preservative or bactericide component content of 0.05 mass % or less of the total water-based paint.

11. A method for defoaming water-based paints, comprising adding the water-soluble silicone defoamer composition according to any one of claims 1 to 7 in an amount calculated as solids to the solids of one or more water-based paints.

12. A method for preserving the quality of a water-based paint, comprising adding the water-soluble silicone defoamer composition according to any one of claims 1 to 7 in an amount calculated as solids to the solids content of one or more types of water-based paint.

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