WO2016136437A1

WO2016136437A1 - Defoaming-property improver, defoamer containing same, and aqueous coating composition

Info

Publication number: WO2016136437A1
Application number: PCT/JP2016/053567
Authority: WO
Inventors: 北村匠; 島林克臣
Original assignee: サンノプコ株式会社
Priority date: 2015-02-28
Filing date: 2016-02-05
Publication date: 2016-09-01
Also published as: CN107106940B; JP6772404B2; JPWO2016136437A1; CN107106940A

Abstract

The purpose of the present invention is to provide a defoaming-property improver with which it is possible to suppress cissing, and to dramatically enhance defoaming properties, merely by compounding a hydrophobic compound with the improver. The present invention is a defoaming-property improver formed by the inclusion of a compound represented by formula 1 or a compound represented by formula 2. X is a residue obtained by removing a hydroxyl group from an alcohol condensate; Y is an oxygen atom or 1,4-dioxa-2-oxobutylene; OA is oxyalkylene; Z is a group represented by ‒R, ‒C(=O)‒R, ‒C(=O)‒NH‒R, or ‒CH₂‒CH(‒OH)‒CH₂‒R; R is alkyl, alkenyl, or aryl; S is a residue obtained by removing carboxyl hydrogen atoms from a (co)polymer having (meth)acrylic acid as an essential constituent monomer; M is a hydrogen atom, methyl, or ethyl; a is 0-20; b is 0-10; c is 1-16; d is 0-10; e is 0-10; and f is 2-10.

Description

Antifoaming improver, antifoaming agent containing the same, and aqueous coating composition

The present invention relates to an antifoaming improver, an antifoaming agent containing the same, and an aqueous coating composition.

Conventionally, “a defoaming agent mixture composed of paraffinic hydrocarbon and hydrophobic silicic acid by reacting hydrophilic silicic acid dispersed in liquid paraffinic hydrocarbon with alkylchlorosilane while removing the generated hydrogen chloride. (Patent Document 1),
“By contacting the hydrophilic silica particles with a hydrophobic agent in an inert liquid medium for up to 4 hours at a temperature in the range of about 100-140 ° C. under vacuum in the absence of a catalyst, An antifoaming composition containing hydrophobic silica particles comprising forming a dispersion of hydrophobic silica particles in an inert, hydrophobic medium is known (Patent Document 2).

JP 62-227414 A (corresponding foreign patent application; USP 480401A, EP 0236893A2) Japanese translation of PCT publication No. 2003-523816 (corresponding international patent application; WO00 / 58213)

However, the antifoaming agents described in Patent Documents 1 and 2 have a problem of poor antifoaming properties. Therefore, the object of the present invention is to suppress repellency and drastically improve the antifoaming property only by adding it to the antifoaming agents and the like (including hydrophobic compounds etc.) described in Patent Documents 1 and 2. It is to provide an antifoaming improver.

The feature of the antifoam improver of the present invention is that it contains the compound (P1) represented by the formula (1) or the compound (P2) represented by the formula (2).

-R (3)
-C (= O) -R (4)
—C (═O) —NH—R (5)
—CH ₂ —CH (—OH) —CH ₂ —R (6)

X is a reaction residue obtained by removing a hydroxyl group from a condensate of tri to octavalent alcohols, Y is an oxygen atom or a 1,4-dioxa-2-oxobutylene group {—OC (═O) CH ₂ O—. Divalent group}, OA is an oxyalkylene group having 2 to 4 carbon atoms, H is a hydrogen atom, OH is a hydroxyl group, Z is a monovalent group represented by any one of formulas (3) to (6), R is an alkyl group having 7 to 24 carbon atoms, an alkenyl group having 7 to 23 carbon atoms or an aryl group having 7 to 15 carbon atoms, C is a carbon atom, O is an oxygen atom, N Is a nitrogen atom, S is a reaction residue obtained by removing a hydrogen atom of a carboxyl group from a (co) polymer having (meth) acrylic acid as an essential constituent monomer, M is a hydrogen atom, methyl group or ethyl group, a is An integer from 0 to 20, b is an integer from 0 to 10, c is an integer from 1 to 16, and d is an integer from 0 to 10 (However, the sum of b, c and d is 4 to 16.), e is an integer of 0 to 10, and f is an integer of 2 to 100 (however, the sum of e and f is 2 to 110.) Represents.

The feature of the antifoaming agent of the present invention is summarized as comprising the antifoaming improver and the hydrophobic compound (E).

The feature of the water-based coating composition of the present invention is that it is composed of a water-based coating material and the antifoaming agent.

The antifoaming improver of the present invention can effectively prevent repellency and drastically improve the defoaming property only by adding it to a conventional antifoaming agent (including a hydrophobic compound).

Since the antifoaming agent of the present invention contains the antifoaming property improver, repellency is suppressed and excellent antifoaming properties are exhibited.

Since the aqueous coating composition of the present invention contains the antifoaming agent (that is, because it contains the antifoaming property improving agent), repelling is suppressed and excellent antifoaming properties are exhibited. Accordingly, the coating film obtained by applying the aqueous coating composition of the present invention does not impair the appearance due to residual foam marks or the like.

<Compound (P1) Represented by Formula (1)>
Examples of the alcohol condensate (X ′) that can constitute the reaction residue (X) obtained by removing the hydroxyl group from the tri- to 8-valent alcohol condensate include trivalent alcohol condensates (ditrimethylolpropane, diglycerin). , Tetraglycerin, hexaglycerin, decaglycerin, hexadecaglycerin, etc.) and tetrahydric alcohol condensates (dipentaerythritol, tripentaerystol, etc.). Of these, from the viewpoint of antifoaming properties and suppression of repellency, a condensate of tri- to tetravalent alcohols is preferred, tetraglycerin, hexaglycerin, decaglycerin and hexadecaglycerin are particularly preferred, and hexaglycerin and decaglycerin are particularly preferred. It is.

The hydroxyl value (mgKOH / g) of the condensate (X ′) of the trivalent to octavalent alcohol that can constitute the reaction residue (X) is preferably 500 to 1600, more preferably 600 to 1500, and particularly preferably. Is 850 to 1400. The hydroxyl value is determined according to “7.1 neutralization titration method” of JIS K0070-1992 (summary: acetylating reagent is added to the sample, heated in a glycerin bath, allowed to cool, and then a phenolphthalein solution is used as an indicator. In addition, titration with a potassium hydroxide ethanol solution is performed to determine the hydroxyl value.
The condensation number of the alcohol condensate (X ′) can be calculated from the hydroxyl value and the molecular weight of the alcohol.

Examples of the oxyalkylene group (OA) having 2 to 4 carbon atoms include oxyethylene, oxypropylene and oxybutylene. Among these, oxyethylene and a mixture of oxyethylene and oxypropylene are preferable from the viewpoint of suppressing repelling.

When plural kinds of oxyalkylene groups are contained in OA, there is no limitation on the bonding order (block shape, random shape and combinations thereof) and content ratio of these oxyalkylene groups, but the block shape or block shape and random shape It is preferable that the combination of these is included, More preferably, it contains a block shape.

When the oxyalkylene group contains oxyethylene, the content ratio (mol%) of oxyethylene is preferably 10 to 90 or 100, more preferably 20 to 75 or 100, particularly based on the total number of moles of the oxyalkylene group. 50 to 65 or 100 is preferable.

A is preferably an integer of 0 to 20, more preferably an integer of 4 to 8. Within this range, antifoaming properties and repellency suppression are further improved.

B is preferably an integer of 0 to 10, more preferably an integer of 0 to 2. Within this range, antifoaming properties and repellency suppression are further improved.

C is preferably an integer of 1 to 16, more preferably an integer of 4 to 12. Within this range, antifoaming properties and repellency suppression are further improved.

D is preferably an integer of 0 to 10, more preferably an integer of 0 to 2. Within this range, antifoaming properties and repellency suppression are further improved.

The sum of b, c and d is preferably an integer from 4 to 16, more preferably an integer from 4 to 12. Within this range, antifoaming properties and repellency suppression are further improved.

Of any one hydrocarbon group (R) selected from an alkyl group having 7 to 24 carbon atoms, an alkenyl group having 7 to 23 carbon atoms and an aryl group having 7 to 15 carbon atoms, an alkyl group having 7 to 24 carbon atoms Examples thereof include heptyl, 2-ethylheptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, heptadecyl, isoheptadecyl, octadecyl, icosyl, heicosyl, tricosyl and tetracosyl.

Among the hydrocarbon groups (R), examples of the alkenyl group having 7 to 23 carbon atoms include heptenyl, 2-ethylheptenyl, octenyl, nonenyl, decenyl, undecenyl, tridecenyl, heptadecenyl, octadecenyl, isoheptadecenyl, nonacosenyl, henicocenyl and Tricocenyl and the like can be mentioned.

Among the hydrocarbon groups (R), examples of the aryl group having 7 to 15 carbon atoms include benzyl, 2-phenylethyl, 4-phenylbutyl, 7-phenylheptyl and 9-phenylnonyl.

Of these hydrocarbon groups (R), octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, pentadecyl, octadecyl, octadecenyl and 2-phenylethyl are preferred.

The compound (P1) represented by the formula (1) can be easily obtained by a known method (alkylene oxide addition reaction, esterification reaction, urethane reaction, epoxy ring-opening reaction, etc.). For example, the compound (P1) is a polyoxyalkylene compound (P1 ′) (Y is an oxygen atom) obtained by addition reaction of an alkylene oxide having 2 to 4 carbon atoms with a condensate (X ′) of a tri to octavalent alcohol. And a carboxylic acid, an isocyanate, or an α-olefin epoxide. Further, a condensate (X ′) of a trivalent to octavalent alcohol and a polyoxyalkylene alkyl ether acetic acid {R— (OA) _a O—CH ₂ CO ₂ H} or a polyoxyalkylene alkenyl ether acetic acid {R— (OA) can be easily obtained by chemical reaction with _{_{_{a O-CH 2 CO 2 H}}} } (Y is 1,4-dioxa-2-oxo-butylene group).

The tri- to 8-valent alcohol condensate (X ′) constituting the reaction residue (X) can be easily obtained from the market. For example, polyglycerin # 310 (polyglycerin, hydroxyl value 1070 mg KOH / g: Sakamoto Yakuhin) Kogyo Co., Ltd.), polyglycerin # 500 (polyglycerin, hydroxyl value 970 mgKOH / g: Sakamoto Pharmaceutical Co., Ltd.), polyglycerin # 750 (polyglycerin, hydroxyl value 890 mgKOH / g: Sakamoto Pharmaceutical Co., Ltd.), PGL06 (poly Glycerin, hydroxyl value 950 mgKOH / g, about 6-mer: Daicel Corporation, PGL10 (polyglycerin, hydroxyl value 850 mgKOH / g, about 10-mer: Daicel Corporation), dipentalit (dipentaerythritol: Koei Chemical Industry) ) And tri-pentalit (tripentaerythrito) : It includes the honored chemical industry), and the like.

The 3- to 8-valent alcohol condensate (X ′) may be obtained by further dehydration condensation using the 3- to 8-valent alcohol or condensate (X ′) as a raw material. The product (X ′) may be obtained by addition reaction of glycidol. That is, for example, a dehydration condensation of a trihydric alcohol and a tetrahydric alcohol or an addition reaction of a tetrahydric alcohol and glycidol may be performed to obtain a condensate of different alcohols.

When Z is a group represented by the formula (3), the compound (P1) is obtained by condensing a tri- to octavalent alcohol condensate (X ′) with a polyoxyalkylene alkyl ether acetic acid or a polyoxyalkylene alkenyl ether acetic acid. It can be easily obtained by an esterification reaction (refer to JP 2011-005373 A and the like regarding the esterification reaction).

Examples of polyoxyalkylene alkyl ether acetic acid and polyoxyalkylene alkenyl ether acetic acid include 2- (octyl polyoxyethyleneoxy) acetic acid <2, 3 or 4 mol>, 2- (decylpolyoxyethyleneoxy) acetic acid <2, 3 or 4 mol>, 2- (dodecyl polyoxyethyleneoxy) acetic acid <2, 3 or 4 mol>, 2- (dodecyl polyoxyethyleneoxy) acetic acid <4, 5 or 6 mol>, 2- (dodecyl polyoxyethyleneoxy) ) Acetic acid <5, 10 or 20 moles> and polyoxyethylene oleyl ether acetic acid <7, 9 or 11 moles> and the like (indicated by <> represents the number of moles of oxyethylene in one molecule. is there.).

Polyoxyalkylene alkyl ether acetic acid and polyoxyalkylene alkenyl ether acetic acid are readily available from the market, for example, Kao Akipo RLM-45 (2- (dodecyl polyoxyethyleneoxy) acetic acid <4 mol and 5 mol mixture; average 4.5 mol>: Kao Corporation), Kao Akipo RLM-100 (2- (dodecylpolyoxyethyleneoxy) acetic acid <10 mol>: Kao Corporation), Beaulite (registered trademark) LCA-H (2- (dodecyl) Polyoxyethyleneoxy) acetic acid <4 mol>: Sanyo Kasei Kogyo Co., Ltd.), Viewlite LCA-25NH (2- (dodecyl polyoxyethyleneoxy) acetic acid <3 mol>: Sanyo Kasei Kogyo Co., Ltd.) and Akipo LS-O90 (Polyoxyethylene oleyl ether acetic acid <9 mol>: Flower Co., Ltd.) and the like.

In the case where Z is a group represented by the formula (4), the compound (P1) is obtained by subjecting a polyoxyalkylene compound (P1 ′) to an addition reaction between a tri- to octavalent alcohol condensate (X ′) and an alkylene oxide. Can be obtained by an esterification reaction of a polyoxyalkylene compound (P1 ′) and a carboxylic acid (refer to JP 2011-005373 A).

Examples of the carboxylic acid include monocarboxylic acids having 8 to 25 carbon atoms, such as octanoic acid, decanoic acid, dodencanic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, docosanoic acid, tetracosanoic acid, octadecenoic acid, octadecaenoic acid. Examples include dienoic acid and phenylpropionic acid. Of these, octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, octadecenoic acid, octadecanedienoic acid and phenylpropionic acid are preferred, and dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid are more preferred. And octadecenoic acid.

When Z is a group represented by the formula (5), the compound (P1) can be obtained by a chemical reaction between the polyoxyalkylene compound (P1 ′) and the monoisocyanate (about the reaction with the monoisocyanate, (See Kaiho 2009-197112, etc.).

Monoisocyanates include monoisocyanates having 8 to 25 carbon atoms, and examples include octyl isocyanate, octadecyl isocyanate, dicyclohexyl isocyanate, nonylcyclohexyl isocyanate, octadecenyl isocyanate, ethylphenyl isocyanate and nonylphenyl isocyanate. Of these, octyl isocyanate, octadecyl isocyanate, and nonyl cyclohexyl isocyanate are preferable, and octyl isocyanate is more preferable.

When Z is a group represented by the formula (6), the compound (P1) can be obtained by a chemical reaction between a polyoxyalkylene compound (P1 ′) and an α-olefin epoxide (with an α-olefin epoxide). (See JP 2005-54128 A for the reaction).

The α-olefin epoxide includes α-olefin monoepoxide having 8 to 25 carbon atoms, such as 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxide decane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane, 1,2-epoxydecene, 1,2-epoxytetradecene, 1-phenyl-1,2-epoxyethane, 1-nonylphenyl-1,2-epoxy Ethane and the like. Of these, 1,2-epoxydecane, 1,2-epoxydodecane and 1,2-epoxytetradecane are preferable, and 1,2-epoxydodecane is more preferable.

<Compound (P2) Represented by Formula (2)>
As a (co) polymer capable of constituting a reaction residue (S) obtained by removing a hydrogen atom of a carboxyl group from a (co) polymer having (meth) acrylic acid as an essential constituent monomer, (meth) acrylic acid is As long as it is an essential constituent monomer, another monomer may be included as an optional constituent monomer, but it is preferable that no other monomer is included. {Therefore, S represents (meth) acrylic acid. A reaction residue obtained by removing a hydrogen atom of a carboxyl group from a polymer as a constituent monomer is preferable, that is, a reaction residue obtained by removing a hydrogen atom of a carboxyl group from poly (meth) acrylic acid. . }.

Other monomers are not limited as long as they can be copolymerized with (meth) acrylic acid. For example, (meth) acrylic acid ester {methyl (meth) acrylate and ethyl (meth) acrylate} and vinyl And monomers {styrene, α-methylstyrene, t-butylstyrene, chlorostyrene, maleic acid, etc.} and the like.

When other monomers are included as constituent monomers, the content (mol%) of the (meth) acrylic acid unit is based on the total number of moles of the (meth) acrylic acid unit and the other monomer units. 10 to 99 are preferable, and 50 to 90 are more preferable. In this case, the content (mol%) of the other monomer units is preferably 1 to 90, more preferably based on the total number of moles of the (meth) acrylic acid unit and the other monomer units. 10 to 50.

The oxyalkylene group (OA) and hydrocarbon group (R) having 2 to 4 carbon atoms are the same as in the case of the compound (P1).

E is preferably an integer of 0 to 10, more preferably an integer of 0 to 5. Within this range, the defoaming property and suppression of repelling are further improved.

F is preferably an integer of 2 to 100, more preferably an integer of 5 to 50. Within this range, the defoaming property and suppression of repelling are further improved.

The sum of e and f is preferably an integer of 2 to 110, more preferably an integer of 5 to 55. Within this range, the defoaming property and suppression of repelling are further improved.

The compound (P2) represented by the formula (2) can be easily obtained by a known method (radical polymerization reaction, transesterification reaction, etc.). For example, the compound (P2) can be obtained by a known polymerization method using an alkyl chain-terminated polyalkylene glycol mono (meth) acrylate or an alkenyl chain-terminated polyalkylene glycol mono (meth) acrylate as an essential constituent monomer. Moreover, after preparing poly (meth) acrylic acid ester by the well-known polymerization method by using methyl ester or ethyl ester of (meth) acrylic acid as an essential constituent monomer, this and polyoxyalkylene alkyl ether or polyoxyalkylene are prepared. It can also be obtained by a transesterification reaction with an alkenyl ether (a known method).

The alkyl chain-terminated polyalkylene glycol mono (meth) acrylate or alkenyl chain-terminated polyalkylene glycol mono (meth) acrylate has a group represented by {— (OA—) aR} in the formula (2) (meth) Acrylate {CH ₂ ═CHCOO— (OA—) aR or CH ₂ ═C (CH ₃ ) COO— (OA—) aR}. Such monomers can be easily obtained from the market. For example, Blemmer AME-400 (methoxypolyethylene glycol acrylate: NOF Corporation; “Blemmer” is a registered trademark of the company), Blemmer ALE- 200 (lauroxy polyethylene glycol acrylate: NOF Corporation), BLEMMER PME-100 (methoxy polyethylene glycol methacrylate: NOF Corporation), BLEMMER PME-200 (methoxy polyethylene glycol methacrylate: NOF Corporation), BLEMMER PME-400 (Methoxypolyethylene glycol methacrylate: NOF Corporation), BLEMMER PLE-200 (Lauroxy polyethylene glycol methacrylate: NOF Corporation) and the like.

Examples of the polyoxyalkylene alkyl ether or polyoxyalkylene alkenyl ether include alcohol {HO- (OA-) aR} having a group represented by {-(OA-) aR} in the formula (2).

The antifoam improver of the present invention may contain both the compound (P1) represented by the formula (1) and the compound (P2) represented by the formula (2).
The antifoaming improver of the present invention may contain a thickener, a dispersant, an antiseptic, an antifreezing agent and / or a diluent solvent.

Thickeners include xanthan gum, locust bean gum, guar gum, carrageenan, alginic acid and its salts, tragacanth gum, magnesium aluminum silicate, bentonite, synthetic hydrous silicic acid, and synthetic polymer type thickeners containing carboxyl groups (as trade names, For example, SN thickener 636, SN thickener 641; San Nopco Corporation), associative thickeners containing polyoxyethylene chains (trade names such as SN thickener 625N, SN thickener 665T; San Nopco Corporation), and the like.

Examples of the dispersant include polyacrylic acid (salt), partially saponified polyvinyl alcohol, and sulfated polyvinyl alcohol.

Examples of antifreezing agents include ethylene glycol, propylene glycol, and glycerin.

As the preservative, known preservatives (bacterial / antifungal dictionary, published by the Japanese Society for Antibacterial and Fungicidal Society, 1st edition, 1986, page 1-32, etc.) can be used. Formalin and 5-chloro-2 -Methyl-4-isothiazolin-3-one and the like.

As the diluting solvent, known solvents (solvent handbook, Kodansha, published in 1976, pages 143-881) and the like can be used, and examples thereof include water, butyl cellosolve, propylene glycol monopropyl ether and 1-butanol.

The antifoamer of the present invention can constitute an antifoamer together with the hydrophobic compound (E).
Examples of the hydrophobic compound (E) include mineral oils, animal and vegetable oils, synthetic lubricating oils, and antifoaming agents containing these.
Mineral oil includes known mineral oils, and examples include spindle oil, machine oil, and refrigerator oil. Known animal and vegetable oils include fish oil, rapeseed oil, soybean oil, sunflower seed oil, cottonseed oil, peanut oil, rice bran oil, corn oil, safflower oil, olive oil, sesame oil, evening primrose oil, palm oil, shea fat , Monkey fat, cacao butter, coconut oil, palm kernel oil and the like. The synthetic lubricating oil includes known synthetic lubricating oils, and examples thereof include polyolefin oil (α-olefin oil), polyglycol oil, polybutene oil, alkylbenzene oil (alkylate oil), and isoparaffin oil.

As the antifoaming agent, known antifoaming agents and those containing mineral oil, animal and vegetable oils and / or synthetic lubricating oil can be used. The antifoaming agent may contain a wax component such as polyethylene oxide, an amide component such as fatty acid polyamide, a metal soap or hydrophobic silica particles.

The hydrophobic compound (E) preferably contains mineral oil or synthetic lubricating oil, and more preferably has a kinematic viscosity (mm ² / s; 40 ° C.) of 0.5 to 30 (preferably 0.8 to 27). More preferably, it includes 1 to 25), and includes mineral oil and synthetic lubricating oil having an aniline point of 50 to 100 ° C.

The above-mentioned mineral oil, animal and vegetable oil and synthetic lubricating oil can be easily obtained from the market. Examples of the mineral oil and synthetic lubricating oil include Cosmo SC22 (21 mm ² / s), Cosmo SP10 (10 mm ² / s), and Cosmo RC Spindle. Oil (10 mm ² / s), Cosmo RB spindle oil (15 mm ² / s), Cosmo Neutral 150 (32 mm ² / s), Cosmo Pure Spin G (21 mm ² / s) and Cosmo Pure Spin E (5 mm ² / s) (Cosmo Oil Lubricants Co., Ltd., “Cosmo” is a registered trademark of Cosmo Oil Co., Ltd.); Nisseki Super Oil C (93 mm ² / s), Nisseki Super Oil D (141 mm ² / s) and Nisseki Super oil B (54 mm ² / s) (Shin Nippon Oil Co., Ltd.); stanol 43N (27 mm ² / s), stanol 52 (56 mm ² / s), stanol 69 (145 mm ² / s), stanol 35 (9 mm ² / s) and stanol LP35 (11 mm ² / s) (Esso Oil Co., Ltd.); and Fucor SH spin (9 mm ² / s) , Fukkor NT100 (21 mm ² / s), Fukkor NT150 (28 mm ² / s), Fukkor NT200 (39 mm ² / s), Fukkor NT60 (10 mm ² / s) and Fukkor ST machine (9 mm ² / s) (Fuji Kosan Co., Ltd.) The company “Fukkor” is a registered trademark of Shin Nippon Oil Co., Ltd.) (numbers in parentheses indicate “kinematic viscosity (40 ° C.)”), and animal and vegetable oils include fine oil N, Fine oil LR-1, Fine oil ISB-12 (Miyoshi Oil & Fat Co., Ltd.) and the like.

The antifoaming agent can be easily obtained from the market. For example, as an antifoaming agent containing hydrophobic silica, SN deformer 318, SN deformer 154 and Nopco 8034, as an antifoaming agent containing a wax component, SN deformer 1340, SN Examples of the antifoaming agent including the deformer 1360 and the metal soap include Nopco NXZ (all manufactured by San Nopco Co., Ltd.).

The weight ratio {(antifoam improver) :( hydrophobic compound (E))} between the antifoam improver and the hydrophobic compound (E) is preferably 1:99 to 25:75, more preferably 2 : 98 to 10:90, particularly preferably 3:97 to 5:95. Within this range, antifoaming properties and repellency suppression are further improved.

If the antifoamer of this invention contains said antifoamer improvement agent and hydrophobic compound (E), there will be no restriction | limiting in a manufacturing method, A well-known mixing method etc. can be applied.

The antifoaming agent of the present invention may be used as it is, diluted with a solvent, water, aqueous solution or the like, or used after being supported on a powder of silica, calcium carbonate or the like.

The antifoaming agent of the present invention includes antifoaming agents for paints, antifoaming agents for cement building materials (concrete, mortar, plaster, etc.) and various manufacturing processes (paper making process, fermentation process, wastewater treatment process, monomer stripping process and polymer). It can be applied as an antifoaming agent and the like. Among these, it is suitable as an antifoaming agent for paints and an antifoaming agent for building materials, is further suitable as an antifoaming agent for paints, and is most suitable as an antifoaming agent for aqueous coating materials.

Suitable water-based coating materials include coating materials containing an acrylic binder, vinyl acetate binder, styrene binder, halogenated olefin binder, urethane binder, acrylic-silicone binder, or fluorine binder.

When the antifoaming agent of the present invention is applied to a paint, the antifoaming agent of the present invention includes (1) a method of adding at the time of pigment dispersion and / or (2) after preparation of the paint. In addition, when applied to various production processes, the antifoaming agent of the present invention is added to (1) raw material supply, (2) before heating and / or decompression treatment, and / or (3) final finishing process, etc. Either method can be used.

The addition amount of the antifoaming agent of the present invention can be appropriately determined depending on the application object, application, etc. For example, when the antifoaming agent of the present invention is used as an antifoaming agent for an aqueous coating material, The content (% by weight) is preferably 0.05 to 5, more preferably 0.1 to 4.5, particularly preferably 0.2 to 4, and most preferably 0.8 based on the weight of the aqueous coating material. 3 to 3. Within this range, the defoaming property and suppression of repelling are further improved.

The water-based coating material to which the antifoaming agent of the present invention is added can be applied to an object to be coated by an ordinary method, such as brush coating, roller coating, air spray coating, airless coating, roll coater coating, and flow coater coating. Although a coating method or the like can be applied, the effect is particularly remarkable during brush coating and roller coating.

Unless otherwise specified, parts means parts by weight and% means% by weight. The weight average molecular weight (Mw) was measured under the following conditions.
Model: HLC-8320GPC EcoSEC (Tosoh Corporation)
Column: TSK gel SuperHZ4000 (Tosoh Corporation)
Column temperature: 40 ° C
Detector: RI
Solvent: Tetrahydrofuran Flow rate: 0.500 mL / min
Sample concentration: 0.1%
Injection volume: 20 μL
Standard: Polyoxyethylene glycol (Tosoh Corporation; TSK STANDARD POLYETHYLENE OXIDE)
Data processor: GPC workstation EcoSEC-WS (Tosoh Corporation)

The number of condensations of the 3- to 8-valent alcohol condensate (X ′) was calculated from the hydroxyl value (mgKOH / g) and the molecular weight of glycerin.

<Example 1>
236 parts (0.5 mole part) of PGL6 {polyglycerin: approximately hexamer of glycerin: glycerin, hydroxyl value 950 mg KOH / g: Daicel Co., Ltd.} and 4 parts of sodium hydroxide were put into a pressure-resistant reaction vessel, and then heated to 130 ° C. And dehydrated under reduced pressure of 0.6 to 1.3 kPa for 2 hours. Subsequently, 704 parts (16 mole parts) of ethylene oxide (EO) was added dropwise at 160 ° C. over 3 hours while maintaining the reduced pressure, and stirring was further continued at 160 ° C. for 1 hour to react the remaining (EO). Next, alkaline adsorbent {synthetic aluminosilicate; Kyoward 600, Kyowa Chemical Industry Co., Ltd., and "Kyoward" are registered trademarks of the company. } Is removed (hereinafter referred to as “catalyst removal treatment”). } To obtain a polyoxyalkylene compound (A1: polyglycerin ethylene oxide 32 mol adduct).

Subsequently, 940 parts (0.5 mole part) of polyoxyalkylene compound (A1), Lunac L-98 {Kao Corporation, lauric acid (98% or more), "Lunac" is a registered trademark of the company in a pressure-resistant reaction vessel. It is. } 800 parts (4 mole parts) and 4 parts of methanesulfonic acid {reagent special grade, Wako Pure Chemical Industries, Ltd.} are charged with nitrogen gas to 0.3 MPa, and then discharged to 0.12 MPa. This operation was repeated three times (hereinafter, the operation using this nitrogen gas is abbreviated as “nitrogen replacement”), and then the temperature was raised to 150 ° C. Subsequently, the pressure was gradually reduced by a vacuum pump, and the reaction was carried out at 0.6 to 1.3 kPa at 150 ° C. for 12 hours to produce an antifoam improver of the present invention (S1: 8 mol ester of lauric acid of polyglycerin ethylene oxide 32 mol adduct). Body).

<Example 2>
In the same manner as in Example 1 except that “ethylene oxide (EO) 704 parts (16 mole parts)” was changed to “ethylene oxide (EO) 1408 parts (32 mole parts)”, the antifoam improver ( S2: Polyglycerin ethylene oxide 64 mol adduct lauric acid 8 mol esterified product) was obtained.

<Example 3>
"PGL6 {polyglycerin: about 6-mer of glycerin} 234 parts (0.5 mol part)" was replaced with "PGL10 {polyglycerin: about 10-mer of glycerin, hydroxyl value 850 mgKOH / g: Daicel Corporation} 198 parts ( "0.25 mol part)", "ethylene oxide (EO) 704 parts (16 mol parts))" changed to "ethylene oxide (EO) 1056 parts (24 mol parts)" and "Lunac L-98 {Lauric acid} 800 parts (4 mole parts) "was changed to" Lunac L-98 {lauric acid} 500 parts (2.5 mole parts) "in the same manner as in Example 1 except that A foamability improver (S3: polyglycerin ethylene oxide 96 mol adduct of lauric acid 10 mol ester) was obtained.

<Example 4>
“234 parts (0.5 mole part) of PGL6” was changed to “PGL10 {polyglycerin: about 10-mer of glycerin, hydroxyl value 850 mg KOH / g: Daicel Corporation} 198 parts (0.25 mole part)”. In the same manner as in Example 1, except that “ethylene oxide (EO) 704 parts (16 mole parts)” was changed to “ethylene oxide (EO) 1056 parts (24 mole parts)”, the polyoxyalkylene compound (A2 : Polyglycerin ethylene oxide 96 mol adduct), 1254 parts (0.25 mol part) of polyoxyalkylene compound (A2) and 5 parts of potassium hydroxide were charged into a pressure resistant reactor and dehydrated under reduced pressure at 120 ° C. Eposizer M-24 {DIC Corporation, 1,2-epoxyoctadecane, "Eposizer" is a registered trademark of the company. is there. } 804 parts (3 mole parts) were charged, and then the pressure was gradually reduced by a vacuum pump while raising the temperature, and the mixture was reacted at 0.6 to 1.3 Pa at 120 ° C. for 1 hour to obtain the antifoam improver (S4 : 1,2-epoxyoctadecane 12 mol adduct of polyglycerin ethylene oxide 96 mol adduct).

<Example 5>
In a pressure resistant reactor, SC-E 1000 {Sakamoto Yakuhin Kogyo Co., Ltd., polyglycerin (glycerin dimer) ethylene oxide 20 mol adduct, hydroxyl value: 208 mgKOH / g} 1079 parts (1 mol part), NAA34 {day Oil Co., Ltd., oleic acid, “NAA” are registered trademarks of the company. } 1130 parts (4 mole parts) and 4 parts of methanesulfonic acid {Wako Pure Chemical Industries, Ltd.} were charged, “nitrogen replacement” was performed using nitrogen gas, and the temperature was raised to 150 ° C. Next, the pressure is gradually reduced by a vacuum pump, and the reaction is carried out at 0.6 to 1.3 kPa at 150 ° C. for 12 hours to produce an antifoam improver of the present invention (S5: esterification of 20 mol of polyglycerin ethylene oxide adduct with 4 mol of oleic acid). Body).

<Example 6>
"SC-E 1000 {ethylene oxide adduct of polyglycerin} 1079 parts (1 mol)" is replaced with "PGL10 {Daicel Co., Ltd., polyglycerin, approximately 10-mer of glycerin, hydroxyl value: 850 mgKOH / g} 792 parts (1 "NAA34 {oleic acid} 1130 (4 mol parts)" is changed to "Bulite LCA-H {Sanyo Chemical Industries, 2- (dodecylpolyoxyethyleneoxy) acetic acid (1 molecule)""Burelite" is a registered trademark of the company. } 4180 parts (10 mole parts) ", except that the antifoam improver of the present invention (S6: 1 mole of polyglycerin and 2- (dodecylpolyoxyethyleneoxy) acetic acid 10) was the same as in Example 5. Ester with mol).

<Example 7>
While heating 40 parts of isopropyl alcohol to reflux temperature and stirring and refluxing it, ALE-200 {NOF Corporation, Lauroxy-polyethylene glycol-acrylate: 4 moles of oxyethylene in one molecule} 20 parts (0.05 mol part) and a monomer solution consisting of 20 parts of isopropyl alcohol and a catalyst solution consisting of 1 part of dimethyl-2,2′-azobis (2-methylpropinate) and 19 parts of isopropyl alcohol are added dropwise simultaneously. The monomer solution was dropped in 3 hours, and the catalyst solution was dropped in 2 hours. After completion of these droppings, the mixture was aged for 3 hours while stirring and refluxing. Thereafter, isopropyl alcohol was distilled off under reduced pressure to obtain an antifoam improver (S7: poly (lauroxy-polyethylene glycol-acrylate)) of the present invention. The weight average molecular weight (Mw) of the antifoam improver (S7) was 2100.

<Example 8>
40 parts of methyl ethyl ketone is heated to reflux temperature, and while stirring and refluxing, it consists of 20 parts (0.05 mol part) of ALE-200 {NOF Corporation, Lauroxy-polyethylene glycol-acrylate} and 20 parts of methyl ethyl ketone. The monomer solution and a catalyst solution consisting of 1 part of dimethyl-2,2′-azobis (2-methylpropinate) and 19 parts of methyl ethyl ketone were simultaneously added dropwise, and the monomer solution was dropped in 3 hours, The catalyst solution was dropped in 2 hours. After completion of these droppings, the mixture was aged for 3 hours while stirring and refluxing. Thereafter, methyl ethyl ketone was distilled off under reduced pressure to obtain an antifoam improver (S8: poly (lauroxy-polyethylene glycol-acrylate)) of the present invention. The weight average molecular weight (Mw) of the antifoam improver (S8) was 13000.

<Example 9>
Hydrophobic compound (e1) {Cosmo SC-22, mineral oil, Cosmo Oil Lubricants Co., Ltd.} 40 parts is heated to 80 ° C. and stirred at 80 ° C., and then ALE-200 {Nippon Oil Co., Ltd., Lauroxy -Polyethylene glycol-acrylate} monomer solution consisting of 20 parts (0.05 mol part) and 20 parts of hydrophobic compound (e1), 1 part of dimethyl-2,2'-azobis (2-methylpropinate) and A catalyst solution comprising 19 parts of the hydrophobic compound (e1) was simultaneously added dropwise, the monomer solution was dropped in 3 hours, and the catalyst solution was dropped in 2 hours. After completion of these droppings, the mixture was aged at 80 ° C. for 3 hours with stirring to obtain a hydrophobic compound solution containing the antifoam improver (S9: poly (lauroxy-polyethylene glycol-acrylate)) of the present invention. The weight average molecular weight (Mw) of the antifoam improver (S9) was 20,000. In addition, the weight average molecular weight was measured for the hydrophobic compound solution, and was calculated by excluding the hydrophobic compound (e1) portion.

<Example 10>
"PLE-200 {Nichi Oil Co., Ltd., Lauroxy-polyethylene glycol-methacrylate" in one molecule The antifoam improver (S10: poly (lauroxy-polyethylene glycol-) of the present invention was used in the same manner as in Example 7, except that the number of moles of oxyethylene was 4 moles} 20 parts (0.05 mole parts) ”. Methacrylate)) was obtained. The weight average molecular weight (Mw) of the antifoam improver (S10) was 2300.

<Example 11>
"ALE-200 {Lauroxy-polyethylene glycol-acrylate} 20 parts (0.05 mole part)" is replaced with "ALE-200 {Lauroxy-polyethylene glycol-acrylate} 10 parts (0.025 mole part), PLE-200 {lauroxy -Polyethylene glycol-methacrylate} 10 parts (0.025 mole part) ", except that the antifoam improver (S11: poly (lauroxy-polyethylene glycol-acrylate) of the present invention was used in the same manner as in Example 7. / Lauroxy-polyethylene glycol-methacrylate)). The weight average molecular weight (Mw) of the antifoam improver (S11) was 2200.

<Example 12>
“ALE-200 {Lauroxy-polyethylene glycol-acrylate} 20 parts (0.05 mol)” is replaced with “ALE-200 {lauroxy-polyethylene glycol-acrylate} 17 parts (0.0425 mol), ethyl acrylate {Japan Catalyst Co., Ltd.} 3 parts (0.03 mol parts) ”except that the antifoam improver (S12: poly (lauroxy-polyethylene glycol-methacrylate / acrylic) of the present invention was used in the same manner as in Example 8. Ethyl acid)) was obtained. The weight average molecular weight (Mw) of the antifoam improver (S12) was 11000.

<Example 13>
3.8 parts (1 mole part) of unisafe MM-15K {polyoxypropylene tetradecyl ether: 1-tetradecyl alcohol propylene oxide adduct: NOF Corporation} and 4 parts of sodium hydroxide are charged into a pressure-resistant reaction vessel. After that, dehydration was performed at 130 ° C. under reduced pressure of 0.6 to 1.3 kPa for 2 hours. Next, 220 parts (5 parts by mole) of ethylene oxide (EO) was added dropwise at 160 ° C. over 3 hours while maintaining the reduced pressure, and stirring was further continued at 160 ° C. for 1 hour to react the remaining (EO). Then, “catalyst removal treatment” was carried out to obtain a polyoxyalkylene compound (A3: 1-tetradecyl alcohol propylene oxide 3 mol ethylene oxide 5 mol block adduct).

A monomer solution consisting of 20 parts (0.2 mole part) of ethyl acrylate {Nippon Catalysts Co., Ltd.} and 20 parts of isopropyl alcohol while heating and refluxing 40 parts of isopropyl alcohol to the reflux temperature. Then, a catalyst solution consisting of 1 part of dimethyl-2,2′-azobis (2-methylpropinate) and 19 parts of isopropyl alcohol is started to be dropped at the same time, and the monomer solution is dropped in 3 hours. The dripping was completed in time. After completion of these droppings, the mixture was aged for 3 hours while stirring and refluxing, and then isopropyl alcohol was distilled off under reduced pressure to obtain polyethyl acrylate (A4: weight average molecular weight (Mw) was 2000).

Subsequently, 1094 parts (1.8 mole parts) of the polyoxyalkylene compound (A3), 200 parts (0.1 mole parts) of polyethyl acrylate (A4), and methanesulfonic acid {reagent special grade, Wako Pure Chemical Industries, Ltd.} 4 parts were charged, “nitrogen replacement” was performed using nitrogen gas, and the temperature was raised to 120 ° C. Next, the pressure is gradually reduced by a vacuum pump and reacted at 0.6 to 1.3 kPa at 120 ° C. for 12 hours, and the antifoam improver (S13: poly (ethyl acrylate / 1-tetradecyl polyoxypropylene poly) of the present invention is used. Oxyethylene acrylate): molar ratio 1/18) was obtained. The weight average molecular weight (Mw) of the antifoam improver (S13) was 12000.

<Example 14>
Hydrophobic compound (e2) {SN deformer 154, mineral oil-based antifoaming agent, San Nopco Co., Ltd.} 95 parts and antifoaming improver (S1) 5 parts at 25 ° C. Excel Auto equipped with impeller blades It stirred for 15 minutes using the homogenizer {Nippon Seiki Co., Ltd., model ED}, and the antifoamer (DF1) of this invention was obtained.

<Example 15>
The antifoaming agent (DF2) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S2)”.

<Example 16>
The antifoaming agent (DF3) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S3)”.

<Example 17>
The hydrophobic compound (e2) was changed from “95 parts” to “97 parts”, and the “antifoam improver (S1) 5 parts” was changed to “defoamer improver (S4) 3 parts” The antifoaming agent (DF4) of the present invention was obtained in the same manner as Example 14 except for the above.

<Example 18>
The antifoaming agent (DF5) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S5)”.

<Example 19>
The antifoaming agent (DF6) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S6)”.

<Example 20>
The hydrophobic compound (e2) was changed from “95 parts” to “75 parts” and the “antifoam improver (S1) 5 parts” was changed to “25 parts of antifoam improver (S7)” In the same manner as in Example 14, the antifoaming agent (DF7) of the present invention was obtained.

<Example 21>
The antifoaming agent (DF8) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S8)”.

<Example 22>
The hydrophobic compound (e2) was changed from “95 parts” to “76 parts”. “Defoaming improver (S1) 5 parts” was changed to 24 parts of a hydrophobic compound solution containing an antifoaming improver (S9). The antifoaming agent (DF9) of the present invention was obtained in the same manner as in Example 14 except that it was changed.

<Example 23>
The antifoaming agent (DF10) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S10)”.

<Example 24>
The antifoaming agent (DF11) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S11)”.

<Example 25>
The antifoaming agent (DF12) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S12)”.

<Example 26>
The antifoaming agent (DF13) of the present invention was obtained in the same manner as in Example 14 except that the “antifoaming improving agent (S1)” was changed to “antifoaming improving agent (S13)”.

<Comparative Example 1>
The hydrophobic compound (e2) was used as an antifoaming agent (H1) for comparison.

<Comparative example 2>
In accordance with the description in Patent Document 1, SELOSOL R-586 {paraffin wax, Chukyo Yushi Co., Ltd.} 647 parts, paraffin 115 {paraffin, Nippon Seiwa Co., Ltd.} 500 parts, petroleum jelly {Kosuge Pharmaceutical Co., Ltd.} 147 parts Dissolved and heated to 80 ° C. Under a nitrogen atmosphere, the temperature was raised to 120 ° C., and 177 parts of nip seal NA {precipitation silica, Tosoh Silica Co., Ltd.} was added under stirring. After complete homogenization, 106 parts of n-octyltrichlorosilane {Wako Pure Chemical Industries, Ltd.} are added in 20 minutes, and the temperature is gradually increased after adding about 20% of the total amount of alkylchlorosilane. The temperature was lowered to 80 ° C. Thereafter, the mixture was heated to 190 ° C., and the remaining traces of hydrogen chloride were removed while stirring under a reduced pressure of 0.1 kPa. After cooling to room temperature (25 ° C.), the product solidified into a waxy material. The molten product was mixed with spray dried sodium sulfate in a high speed rotating ski mixer. For this purpose, 167 parts of the product were added within 1 minute onto 1500 parts of sodium sulfate preheated to 90 ° C. and stirred for 3 minutes. After cooling to room temperature (25 ° C.), a comparative antifoam (H2) was obtained.

<Comparative Example 3>
According to the description in Patent Document 2, nip seal NA {precipitation silica, Tosoh Silica Co., Ltd.} 100 parts, Cosmo SC 22 {mineral oil, Cosmo Oil Lubricants Co., Ltd.} 800 parts, KF-96-100cs {silicone oil , Shin-Etsu Chemical Co., Ltd.} was mixed and heated to a temperature of 130 ° C., followed by stirring for 2 hours to obtain a comparative antifoaming agent (H3).

<Creation of water-based paint for evaluation of defoaming>
(1. Preparation of emulsion base paint)
An emulsion base paint was prepared by grinding and letdown using an Excel auto homogenizer equipped with impeller blades with the raw material composition shown in Table 1.

Note 1: Dispersant manufactured by San Nopco Co., Ltd. Note 2: Thickener manufactured by Daicel Finechem Co., Ltd. Note 3: Thickener manufactured by San Nopco Co., Ltd. Note 4: Wetting agent manufactured by San Nopco Co., Ltd. Note 5: Calcium carbonate manufactured by Takehara Chemical Co., Ltd. Note 6: Titanium dioxide manufactured by Ishihara Sangyo Co., Ltd.
Note 7: Binder resin manufactured by Dow Chemical Company ("Primal" is a registered trademark of Roam End Hearth Company)
Note 8: Eastman Chemical Co., Ltd. membrane modifier, “Texanol” is a registered trademark of Yoshimura Chemical Co., Ltd.
Note 9: Thickener manufactured by San Nopco

(2. Preparation of emulsion paint)
Excel auto homogenizer with 0.2 parts of antifoams (DF1) to (DF13) or comparative antifoams (H1) to (H3) added to 100 parts of emulsion base paint and equipped with coreless blades The emulsion paint for evaluation was obtained by stirring and mixing at 25 ° C. and 1500 rpm for 2 minutes.

(Defoaming evaluation)
Using a medium wool wool roller (Otsuka Brush Manufacturing Co., Ltd.), apply the emulsion paint onto a 15 cm x 15 cm tin plate, and visually check the amount of foam generated in a 1.5 cm square immediately after (0 seconds) and after 30 seconds. Counted and listed in Table 2. A smaller number means better defoaming properties.

(Evaluation of repelling)
After degreasing a glass plate {thickness 5 mm, cut to 20 × 30 cm) with acetone / cloth, the emulsion paint for evaluation was applied to the applicator so that the wet film thickness was 100 μm under conditions of 25 ° C. and 60% relative humidity. After coating, the surface of the coating film was observed, and the number of cissing marks was counted visually and listed in Table 2. A smaller value means less repelling and is preferable.

The antifoaming agent containing the antifoaming improver of the present invention is superior in repellency suppression and antifoaming properties compared to the antifoaming agent for comparison, and the coating film obtained by applying the paint has a bad appearance. There was no.

The antifoam improver of the present invention can be used for any application because it can suppress repellency and drastically improve the antifoaming property only by adding it to a hydrophobic compound containing a known antifoaming agent or the like. it can. In particular, it is effective when incorporated in an antifoaming agent for aqueous foaming liquids, for example, paper pulp manufacturing industry (pulping process, papermaking process, coating process, etc.), construction industry (papermaking process, etc.), dye industry, dyeing. The present invention can be applied to an antifoaming agent used for bubbles generated in various processes such as industry, fermentation industry, synthetic resin manufacturing industry, synthetic rubber manufacturing industry, ink, paint industry and textile processing industry. Among these, it is suitable as an antifoaming agent for paints, and further suitable as an antifoaming agent for aqueous coating materials.

Claims

An antifoam improver comprising the compound (P1) represented by the formula (1) or the compound (P2) represented by the formula (2).

-R (3)
-C (= O) -R (4)
—C (═O) —NH—R (5)
—CH 2 —CH (—OH) —CH 2 —R (6)
X is a reaction residue obtained by removing a hydroxyl group from a condensate of tri to octavalent alcohols, Y is an oxygen atom or a 1,4-dioxa-2-oxobutylene group {—OC (═O) CH 2 O—. Divalent group}, OA is an oxyalkylene group having 2 to 4 carbon atoms, H is a hydrogen atom, OH is a hydroxyl group, Z is a monovalent group represented by any one of formulas (3) to (6), R is an alkyl group having 7 to 24 carbon atoms, an alkenyl group having 7 to 23 carbon atoms or an aryl group having 7 to 15 carbon atoms, C is a carbon atom, O is an oxygen atom, N Is a nitrogen atom, S is a reaction residue obtained by removing a hydrogen atom of a carboxyl group from a (co) polymer having (meth) acrylic acid as an essential constituent monomer, M is a hydrogen atom, methyl group or ethyl group, a is An integer from 0 to 20, b is an integer from 0 to 10, c is an integer from 1 to 16, and d is an integer from 0 to 10 (However, the sum of b, c and d is 4 to 16.), e is an integer of 0 to 10, and f is an integer of 2 to 100 (however, the sum of e and f is 2 to 110.) Represents.
An antifoaming agent comprising the antifoaming improver according to claim 1 and a hydrophobic compound (E).
The weight ratio {(antifoam improver) :( hydrophobic compound (E))} of the antifoam improver according to claim 1 and the hydrophobic compound (E) is 1:99 to 25:75. The antifoamer according to claim 2.
An aqueous coating composition comprising an aqueous coating material and the antifoaming agent according to claim 2.