JP4232031B2 - Antifoam composition and method for producing the same - Google Patents

Description

The present invention relates to a silicone-based antifoaming agent composition that hardly deteriorates with time even if stored for a long time after being internally added to a foaming liquid, particularly an alkaline foaming liquid, and a method for producing the same .

  Silicone-based antifoaming agents have various excellent properties compared to other antifoaming agents, so that chemical industry, food industry, petroleum industry, textile industry, paper industry, paper pulp industry, pharmaceutical industry, etc. Widely used in processes involving foaming, for example, an oil compound type antifoaming agent obtained by mixing silicone oil such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylvinylpolysiloxane with fine powdered silica, and these oil compounds are surface active An emulsion type antifoaming agent dispersed in water together with the agent is widely used. However, this emulsion type antifoaming agent has a problem that the emulsified particles are destroyed under severe conditions such as high temperature, high alkalinity, and high shearing force, and the defoaming ability is lowered. Self-emulsifying type antifoaming agent (Japanese Patent Publication No. 51-71886, Japanese Patent Publication No. 54-43015, Japanese Patent Publication No. 52-19836, Japanese Patent Publication No. 52-22638), which is a combination of an organopolysiloxane modified with a group and an oil compound. Japanese Patent Publication No. 55-23084 (Patent Documents 1 to 5)] has been proposed.

  However, these silicone-based antifoaming agents may cause problems such as a decrease in defoaming performance due to contact with the foaming liquid for a long time, separation or sedimentation, etc. This is particularly noticeable in the alkaline case.

  Also, if the process involving foaming takes a long time, the antifoaming performance will deteriorate with time, so it will be necessary to add an additional antifoaming agent. Various problems may occur due to the addition of a large amount.

  Various proposals have been made to improve these problems and to further improve the defoaming performance. For example, a method of hydrophobizing silica used in an oil compound with chlorosilane or the like in advance (Japanese Patent Publication No. 52-31836: Patent Document 6), a method of treating silica with a nitrogen-containing organosilicon compound (Japanese Patent Publication No. 51-35556: Patent Document 7), and the like are mentioned, and further improvement of the characteristics is demanded.

Japanese Patent Publication No.51-71886 Japanese Patent Publication No.54-43015 Japanese Patent Publication No.52-19836 Japanese Patent Publication No. 52-22638 Japanese Patent Publication No. 55-23084 Japanese Patent Publication No.52-31836 Japanese Patent Publication No.51-35556

The present invention has been made in view of the above circumstances, and after internal addition to a foaming liquid, particularly an alkaline foaming liquid, there is little occurrence of separation / precipitation and deterioration over time of the defoaming performance even after long-term storage. It aims at providing the antifoamer composition excellent in sustainability, and its manufacturing method .

  As a result of intensive studies to achieve the above object, the present inventor treated a mixture of fine powder silica surface-treated with organopolysiloxane and an organopolysiloxane having specific physical properties in the presence of an alkaline catalyst. The resulting silicone oil compound, polyoxyalkylene-modified organopolysiloxane having a specific structure and physical properties, and, if necessary, a defoamer composition containing a polyoxyalkylene polymer are added internally to a foaming liquid, particularly an alkaline foaming liquid. The present inventors have found that it is excellent in stability and defoaming sustainability, and have made the present invention.

Therefore, the present invention
(A) Silicone oil compound obtained by mixing the following components (i) to (iii) at room temperature to 200 ° C., and neutralizing and removing low-boiling fractions as necessary: 1 to 60% by mass
(I) Essentially hydrophobic organopolysiloxane having a viscosity at 25 ° C. of 10 to 100,000 mm ² / s: 100 parts by mass (ii) Fine powder silica surface-treated with organopolysiloxane: 1 to 20 parts by mass (Iii) As an alkaline catalyst, an alkali metal or alkaline earth metal oxide, hydroxide, alkoxide or siliconate: 0.01 to 3 parts by mass (B) The following general formula (I)
R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³ (I)
[Wherein, R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ² is the following general formula (II)
—R ⁴ —O (CH ₂ CH ₂ O) _a — (CH ₂ (CH ₃ ) CHO) _b —R ⁵ (II)
Wherein R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, R ⁵ is a monovalent organic group selected from a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, an acetyl group, and an isocyan group. , a and b are positive numbers satisfying 3 ≦ a + b ≦ 80 and a / b = 2 / 8~8 / 2,. monovalent organic group represented by), R ³ is R ^1, R ^2, a hydroxyl group Or it is a C1-C6 alkoxy group, x is 5-200, y is an integer of 1-30. ]
One or a mixture of two or more polyoxyalkylene-modified organopolysiloxanes having a viscosity at 25 ° C. of 10 to 10,000 mm ² / s represented by: 10 to 99% by mass
(C) One kind or a mixture of two or more kinds of polyoxyalkylene polymers: 0 to 50% by mass
An antifoam composition comprising:
The following (i) to (iii) Component (i) Essentially hydrophobic organopolysiloxane having a viscosity at 25 ° C. of 10 to 100,000 mm ² / s: 100 parts by mass (ii) Surface-treated with organopolysiloxane Fine powder silica: 1 to 20 parts by mass (iii) Alkali metal or alkaline earth metal oxide, hydroxide, alkoxide or siliconate: 0.01 to 3 parts by mass at room temperature to 200 ° C. And after neutralization and removal of the low-boiling fraction as necessary to obtain a silicone oil compound (A), the silicone oil compound (A),
(B) The following general formula (I)
R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³ (I)
[Wherein, R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ² is the following general formula (II)
—R ⁴ —O (CH ₂ CH ₂ O) _a — (CH ₂ (CH ₃ ) CHO) _b —R ⁵ (II)
Wherein R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, R ⁵ is a monovalent organic group selected from a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, an acetyl group, and an isocyan group. , A and b are positive numbers satisfying 3 ≦ a + b ≦ 80 and a / b = 2/8 to 8/2.), R ³ is R ¹ , R ² , hydroxyl group Or it is a C1-C6 alkoxy group, x is 5-200, y is an integer of 1-30. ]
1 or a mixture of two or more polyoxyalkylene-modified organopolysiloxanes having a viscosity of 10 to 10,000 mm ² / s at 25 ° C.
(C) One or two or more mixtures of polyoxyalkylene polymers (A) Component 1-60 mass%, (B) Component 10-99 mass%, (C) Component 0-50 mass% A method for producing an antifoaming composition, characterized by being mixed in step (b).

  The antifoaming composition of the present invention is excellent in antifoaming sustainability with little deterioration over time even after long-term storage after being internally added to the foaming liquid.

  The silicone oil compound of component (A) constituting the antifoam composition of the present invention is a main component for imparting defoaming properties to this composition, and is essentially an hydrophobic organopolysiloxane. Fine powder silica (ii) surface-treated with (i) and organopolysiloxane is the main component, and these are obtained by treating them in the presence of an alkaline catalyst (iii).

  The organopolysiloxane (i) used for the component (A) is essentially hydrophobic. Here, “essentially hydrophobic” means that even if some functional groups contain hydrophilic groups, the organopolysiloxane as a whole exhibits hydrophobicity.

The essentially hydrophobic organopolysiloxane (i) may be linear or branched, and those represented by the following average composition formula (III) are particularly preferred.
R ⁶ _m SiO _{(4-m) / 2} (III)

In the above formula (III), R ⁶ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, which may be the same or different. Specific examples of the monovalent hydrocarbon group for R ⁶ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, and tridecyl group. , Alkyl groups such as tetradecyl group, hexadecyl group and octadecyl group, cycloalkyl groups such as cyclohexyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group and tolyl group, styryl group, α-methylstyryl group An aralkyl group such as chloromethyl group, a 3-chloropropyl group, or a chloromethyl group in which part or all of the hydrogen atoms bonded to the carbon atom of these groups are substituted with a halogen atom, a cyano group, an amino group, a hydroxyl group, etc. 3,3-trifluoropropyl group, cyanoethyl group, 3-aminopropyl group, N- (β-aminoethyl) -γ-aminopropyl Although and the like, 80 mol% or more of the total R ⁶ in terms of defoaming and economy, and particularly preferably more than 90 mol% are methyl groups. M is a positive number satisfying 1.9 ≦ m ≦ 2.2, preferably 1.95 ≦ m ≦ 2.15. The end of the organopolysiloxane may be blocked with a triorganosilyl group represented by R ⁶ ₃ Si— or may be blocked with a diorganohydroxysilyl group represented by HOR ⁶ ₂ Si—.

The viscosity of this essentially hydrophobic organopolysiloxane (i) measured at 25 ° C. with an Ostwald viscometer is 10 to 100,000 mm ² / s, preferably 50 to 10, from the viewpoint of defoaming and workability. 000 mm ² / s. It is less than 10 mm ² / s leads to a poor antifoaming ability whereas a working viscosity is increased to a silicone oil compound having too greater than 100,000 mm ² / s.

On the other hand, fine powder silica (ii) surface-treated with organopolysiloxane can be obtained, for example, by subjecting fine powder silica raw powder to surface treatment with organopolysiloxane represented by the following composition formula (IV). May be used.
R ⁷ ₂ R ⁸ SiO— (R ⁷ ₂ SiO) _x —SiR ⁷ ₂ R ⁸ (IV)

In the above formula (IV), R ⁷ is the same or different monovalent hydrocarbon group having 1 to 18 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl. Group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, alkyl group such as tetradecyl group, hexadecyl group, octadecyl group, cycloalkyl group such as cyclohexyl group, aryl group such as phenyl group, tolyl group In view of defoaming properties and economy, it is preferable that 80 mol% or more, particularly 90 mol% or more of all R ⁷ are methyl groups. R ⁸ is R ⁷ , a hydroxyl group or a C 1-6 alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group. The viscosity at 25 ° C. as measured by an Ostwald viscometer of this organopolysiloxane is preferably from the viewpoint of workability is 10~1,000mm ² / s, more preferably from 20 to 100 mm ² / s.

The fine silica raw powder may be a known one, and may be either wet silica or dry silica. Examples of these fine powder silica raw materials include precipitated silica, silica xerogel, fumed silica, and the like. Specifically, nipsil (manufactured by Tosoh Silica), silicia (manufactured by Fuji Silysia Chemical), aerosil (manufactured by Nippon Aerosil Co., Ltd.) ) And other commercial products. In addition, the specific surface area by BET method of 100 m ² / g or more 700 meters ² / g or less, particularly 150 meters ² / g or more 500 meters ² / g or less those preferred.

  Surface treatment of fine powder silica can be carried out using a known method, for example, a mixing / dispersing device such as a Henschel mixer, a Laedige mixer, or a high speeder. It can be produced by spraying organopolysiloxane before or while stirring. If necessary, heating and addition of an alkaline catalyst such as aqueous ammonia can be performed. In this case, the treatment is preferably performed at room temperature to 100 ° C., particularly 50 to 80 ° C. for 10 minutes to 2 hours, particularly 15 minutes to 1 hour.

The amount of the surface treatment agent (organopolysiloxane) with respect to the fine powder silica varies depending on the specific surface area of the fine powder silica, but when the BET specific surface area is 100 to 700 m ² / g, 1 to 50 with respect to 100 parts by mass of the fine powder silica. Part by mass, preferably 5 to 30 parts by mass.

  The addition amount of the fine powder silica (ii) surface-treated with the organopolysiloxane is 1 to 20 parts by mass, preferably 5 to 15 parts by mass with respect to 100 parts by mass of the organopolysiloxane (i). When the addition amount is less than 1 part by mass, the defoaming performance is inferior. When the addition amount is more than 20 parts by mass, the viscosity of the silicone oil compound increases and the workability deteriorates.

  The alkaline catalyst (iii) used in the component (A) of the present invention is a known alkaline catalyst used in the polysiloxane transfer reaction, such as oxides, hydroxides, and alkoxides of alkali metals or alkaline earth metals. Alternatively, siliconate or the like can be used, but potassium siliconate and potassium hydroxide are preferable.

  The usage-amount of an alkaline catalyst (iii) is 0.01-5 mass parts with respect to 100 mass parts of organopolysiloxane (i), Preferably it is 0.1-3 mass parts. If the amount is less than 0.01 parts by mass, the effect as a catalyst is weak, and if the amount exceeds 5 parts by mass, the effect of the catalyst is not improved and the cost is disadvantageous.

  Further, the silicone oil compound of the component (A) of the present invention comprises essentially a predetermined amount of hydrophobic organopolysiloxane (i), finely divided silica (ii) surface-treated with the above organopolysiloxane, and alkaline catalyst (iii). And then, after mixing at room temperature to 200 ° C., preferably 100 to 200 ° C., more preferably 150 to 200 ° C., neutralization and removal of low-boiling fractions are performed as necessary. can do.

The mixing treatment time is preferably 10 minutes to 5 hours, particularly 1 to 3 hours. Further, the mixing treatment is preferably performed in an inert atmosphere such as nitrogen.
Neutralization can be performed using organic acids such as 2-chloroethanol, formic acid, and acetic acid, and inorganic acids such as dilute hydrochloric acid and dilute sulfuric acid. The removal of the low boiling point fraction can be performed by a method such as distillation under reduced pressure.

  In the antifoaming agent composition of the present invention, the content of the silicone oil compound (A) is 1 to 60% by mass, preferably 5 to 40% by mass, based on the entire antifoaming agent composition. When the content is less than 1% by mass, the defoaming performance is insufficient, and when the content is more than 60% by mass, the stability and internal stability of the product are deteriorated.

The (B) component polyoxyalkylene-modified organopolysiloxane is for dispersing the aforementioned silicone oil compound, and is represented by the following general formula (I).
R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³ (I)

In the above formula (I), R ¹ is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group , Pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group and other alkyl groups, cyclohexyl group and other cycloalkyl groups, vinyl group, allyl Alkenyl groups such as alkenyl groups, aryl groups such as phenyl groups and tolyl groups, aralkyl groups such as styryl groups and α-methylstyryl groups, or some or all of the hydrogen atoms bonded to carbon atoms of these groups are halogen atoms , Chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, cyanoethyl group, 3 And monovalent hydrocarbon groups such as -aminopropyl group and N- (β-aminoethyl) -γ-aminopropyl group.

R ² is a polyoxyalkylene group represented by the following general formula (II).
—R ⁴ —O (CH ₂ CH ₂ O) _a — (CH ₂ (CH ₃ ) CHO) _b —R ⁵ (II)
In the above formula (II), R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, and examples thereof include an alkylene group and an alkenylene group. Examples thereof include an ethylene group, a propylene group, a butylene group, a pentene group, and a hexene group. Etc. R ⁵ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an acetyl group, or an isocyan group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. a and b are 3 ≦ a + b ≦ 80, preferably 5 ≦ a + b ≦ 60, and a / b = 2/8 to 8/2, preferably a / b = 2.5 / 7.5 to 7.5 / 2. A positive number satisfying .5.

On the other hand, R ³ is the same group as R ¹ or R ² , a hydroxyl group or an alkoxy group having 1 to 6 carbon atoms. Specifically, the groups exemplified as R ¹ and R ² and the alkoxy group include methoxy Group, ethoxy group, propoxy group, butoxy group and the like.

  In the above formula (I), x is an integer of 5 to 200, preferably 20 to 150, and y is an integer of 1 to 30, preferably 1 to 20.

The polyoxyalkylene-modified organopolysiloxane may be used singly or as a mixture of two or more, but the viscosity at 25 ° C. measured with an Ostwald viscometer is 10 to 10,000 mm ² / s. , Preferably 50 to 8,000 mm ² / s, more preferably 500 to 5,000 mm ² / s.

  In the defoamer composition of the present invention, the content of the polyoxyalkylene-modified organopolysiloxane (B) is 10 to 99% by mass, preferably 20 to 70% by mass, based on the total defoamer composition. When the content is less than 10% by mass, the dispersibility of the component (A) with respect to the aqueous foaming liquid is deteriorated, and when it exceeds 99% by mass, the defoaming property of the composition is deteriorated.

The polyoxyalkylene polymer as the component (C) is for improving the dispersibility of the component (A), and it is preferable to use one represented by the following general formula (V).
^{R 9 O- (R 10 O)} z -R 9 (V)
In the above formula (V), R ⁹ is a hydrogen atom or an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, an alkenyl group such as a vinyl group or an allyl group, an acetyl group or a stearoyl group. -20, especially 1-18 monovalent organic groups, which may be the same or different. R ¹⁰ is a divalent hydrocarbon group having 2 to 6 carbon atoms such as an alkylene group such as an ethylene group or a propylene group. In this case, R ¹⁰ may be two or more different groups.

  Moreover, the weight average molecular weight measured by GPC of this polyoxyalkylene polymer is preferably 500 to 5,000, more preferably 1,000 to 4,000. Here, when the weight average molecular weight is less than 500, the product stability of the obtained antifoaming composition may be deteriorated, and when it exceeds 5,000, the viscosity is increased and workability may be deteriorated. In addition, a polyoxyalkylene polymer may be used individually by 1 type, or may use 2 or more types of mixtures.

  In the antifoaming agent composition of the present invention, the content of the polyoxyalkylene polymer (C) is 0 to 50% by mass, preferably 0 to 40% by mass, based on the entire antifoaming agent composition. When it exceeds 50 mass%, the product stability of an antifoamer composition will worsen. In addition, although it can be set as an effective amount when mix | blending, it is preferable to mix | blend 5 mass% or more.

The antifoaming composition of the present invention can be prepared by mixing predetermined amounts of the above-mentioned components according to a conventional method.
The antifoaming composition of the present invention thus obtained can be added to a foaming liquid, particularly an alkaline foaming liquid, so that the performance does not deteriorate over time even when stored for a long period of time, and the internal stability and antifoaming are reduced. It can be excellent in sustainability. In addition, although the addition amount of an antifoamer composition is not specifically limited, 0.001-3 mass% with respect to a foaming liquid, It is preferable to add 0.01-1 mass% especially. Examples of the alkaline foaming liquid include aqueous cutting oil and pulp black liquor.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following example,% shows the mass% and a viscosity is the value in 25 degreeC measured with the Ostwald viscometer.

[Examples 1-6, Comparative Examples 1-4]
The following components (A) to (C) were used in the amounts shown in Table 1 and mixed with a homomixer to prepare an antifoam composition. With respect to this composition, the defoaming property, internal stability, and product stability were evaluated by the methods described below. The results are shown in Table 2.

(A) Silicone oil compound [silicone oil compound (a)]
As an essentially hydrophobic organopolysiloxane, 100 parts by weight of branched dimethylpolysiloxane having a viscosity of 8,000 mm ² / s and containing 0.01 mole fraction of CH ₃ SiO _3/2 units, as finely divided silica Then, 5 parts by mass of the following (A), 3.3 parts by mass of potassium siliconate containing 3% potassium hydroxide as an alkaline catalyst, mixed at 150 ° C. for 3 hours in a nitrogen gas atmosphere, and then 2-chloro Neutralized with ethanol, then low boiling fraction removed.

[Silicone oil compound (b)]
As an essentially hydrophobic organopolysiloxane, 100 parts by weight of dimethylpolysiloxane having a viscosity of 10,000 mm ² / s, 10 parts by weight of the following (B) as fine powder silica, 3 parts of potassium hydroxide as an alkaline catalyst % Of potassium siliconate containing 5% by weight, mixed under nitrogen gas atmosphere at 150 ° C. for 3 hours, neutralized with 2-chloroethanol, and then the low-boiling fraction was removed.

[Silicone oil compound (c)]
As an essentially hydrophobic organopolysiloxane, 100 parts by weight of branched dimethylpolysiloxane having a viscosity of 8,000 mm ² / s and containing 0.01 mole fraction of CH ₃ SiO _3/2 units, as finely divided silica A mixture of 5 parts by mass of the following (A) and 150 ° C. for 3 hours under a nitrogen gas atmosphere.

[Silicone oil compound (d)]
As an essentially hydrophobic organopolysiloxane, 100 parts by weight of branched dimethylpolysiloxane having a viscosity of 8,000 mm ² / s and containing 0.01 mole fraction of CH ₃ SiO _3/2 units, as finely divided silica , 5 parts by weight of Aerosil 200, 3.3 parts by weight of potassium siliconate containing 3% of potassium hydroxide as an alkaline catalyst, mixed at 150 ° C. for 3 hours in a nitrogen gas atmosphere, and then 2-chloroethanol Neutralized and then removed low boiling fraction.

[Fine powder silica]
(Ii) 100 g of Aerosil 300 [manufactured by Nippon Aerosil Co., Ltd., specific surface area of 300 m ² / g] is charged into a Redige mixer, and 20 g of both ends hydroxydimethylpolysiloxane (viscosity 50 mm ² / s) is atomized while stirring. And stirred at 70 ° C. for 30 minutes.

(B) 100 g of Nippil HD-2 [manufactured by Tosoh Silica Co., Ltd., specific surface area of 300 m ² / g] is charged into a Roedige mixer, and 20 g of both ends hydroxydimethylpolysiloxane (viscosity 50 mm ² / s) is stirred. Added as a mist and stirred for 30 minutes at 70 ° C.

(B) Polyoxyalkylene-modified organopolysiloxane [polyoxyalkylene-modified organopolysiloxane (e)]
The average composition is the following formula: R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³
(However, R ¹ and R ³ are —CH ₃ , R ² is —C ₃ H ₆ O (C ₂ H ₄ O) ₂₁ (C ₃ H ₆ O) ₂₁ CH ₃ , x is 135, and y is 15.)
And a viscosity of 2,500 mm ² / s.

[Polyoxyalkylene-modified organopolysiloxane (f)]
The average composition is the following formula: R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³
(However, R ¹ and R ³ are —CH ₃ , R ² is —C ₃ H ₆ O (C ₂ H ₄ O) _25.5 (C ₃ H ₆ O) _8.5 C ₄ H ₉ , x is 30, y is 5 .)
And the viscosity is 1,000 mm ² / s.

[Polyoxyalkylene-modified organopolysiloxane (g)]
The average composition is the following formula: R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³
(However, R ¹ and R ³ are —CH ₃ , R ² is —C ₃ H ₆ O (C ₂ H ₄ O) _9.4 OH, x is 24, and y is 4.)
And the viscosity is 450 mm ² / s.

(C) Polyoxyalkylene polymer [polyoxyalkylene polymer (h)]
Average composition _{CH 2 = CHCH 2 O- (C} 2 H 4 O) 21 (C 3 H 6 O) 21 those represented by -CH _3.

[Polyoxyalkylene polymer (j)]
Average composition _{HO- (C 2 H 4 O)} 25 (C 3 H 6 O) 35 those represented by -H.

"Evaluation methods"
Defoaming (immediately after addition):
A commercially available aqueous cutting fluid with 0.2% by mass of each sample is diluted 30-fold with water, stirred with a homomixer at 6,000 rpm for 2 minutes, and the time until the foam completely disappears after stirring is stopped. It was measured.

Defoaming property (after 50 ° C. × 7 days):
What added 0.2 mass% of each sample to the commercially available aqueous cutting fluid was stored at 50 ° C. for 7 days, then diluted 30 times with water, and stirred with a homomixer at 6,000 rpm × 2 minutes. The time until the foam completely disappeared was measured.

Internal stability:
Appearance of the sample obtained by adding 0.2% by mass of each sample to a commercially available aqueous cutting fluid was stored at 50 ° C. for 7 days.
○: No floating / sedimentation, △: Some floating / sedimentation, ×: Many floating / sedimentation

Product stability:
The state after each sample was stored at 45 ° C. for 7 days was visually observed according to the following criteria.
○: No separation, △: Density separation, ×: Separation

Claims (5)

(A) Silicone oil compound obtained by mixing the following components (i) to (iii) at room temperature to 200 ° C., and neutralizing and removing low-boiling fractions as necessary: 1 to 60% by mass
(I) Essentially hydrophobic organopolysiloxane having a viscosity at 25 ° C. of 10 to 100,000 mm ² / s: 100 parts by mass (ii) Fine powder silica surface-treated with organopolysiloxane: 1 to 20 parts by mass (Iii) As an alkaline catalyst, an alkali metal or alkaline earth metal oxide, hydroxide, alkoxide or siliconate: 0.01 to 3 parts by mass (B) The following general formula (I)
R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³ (I)
[Wherein, R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ² is the following general formula (II)
—R ⁴ —O (CH ₂ CH ₂ O) _a — (CH ₂ (CH ₃ ) CHO) _b —R ⁵ (II)
Wherein R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, R ⁵ is a monovalent organic group selected from a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, an acetyl group, and an isocyan group. , A and b are positive numbers satisfying 3 ≦ a + b ≦ 80 and a / b = 2/8 to 8/2.), R ³ is R ¹ , R ² , hydroxyl group Or it is a C1-C6 alkoxy group, x is 5-200, y is an integer of 1-30. ]
One or a mixture of two or more polyoxyalkylene-modified organopolysiloxanes having a viscosity at 25 ° C. of 10 to 10,000 mm ² / s represented by: 10 to 99% by mass
(C) One kind or a mixture of two or more kinds of polyoxyalkylene polymers: 0 to 50% by mass
An antifoaming agent composition characterized by containing.   (C) Content of a component is 5-50 mass%, The antifoamer composition of Claim 1.   The antifoaming composition according to claim 1 or 2, which is used for an alkaline foaming liquid.   The antifoaming composition according to claim 3, wherein the alkaline foaming liquid is aqueous cutting oil or pulp black liquor. The following (i) to (iii) Component (i) Essentially hydrophobic organopolysiloxane having a viscosity at 25 ° C. of 10 to 100,000 mm ² / s: 100 parts by mass (ii) Surface-treated with organopolysiloxane Fine powder silica: 1 to 20 parts by mass (iii) Alkali metal or alkaline earth metal oxide, hydroxide, alkoxide or siliconate: 0.01 to 3 parts by mass at room temperature to 200 ° C. And after neutralization and removal of the low-boiling fraction as necessary to obtain a silicone oil compound (A), the silicone oil compound (A),
(B) The following general formula (I)
R ¹ ₂ R ³ SiO— (R ¹ ₂ SiO) _x — (R ¹ R ² SiO) _y —SiR ¹ ₂ R ³ (I)
[Wherein, R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ² is the following general formula (II)
—R ⁴ —O (CH ₂ CH ₂ O) _a — (CH ₂ (CH ₃ ) CHO) _b —R ⁵ (II)
Wherein R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, R ⁵ is a monovalent organic group selected from a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, an acetyl group, and an isocyan group. , A and b are positive numbers satisfying 3 ≦ a + b ≦ 80 and a / b = 2/8 to 8/2.), R ³ is R ¹ , R ² , hydroxyl group Or it is a C1-C6 alkoxy group, x is 5-200, y is an integer of 1-30. ]
1 or a mixture of two or more polyoxyalkylene-modified organopolysiloxanes having a viscosity of 10 to 10,000 mm ² / s at 25 ° C.
(C) One or two or more mixtures of polyoxyalkylene polymers (A) Component 1-60 mass%, (B) Component 10-99 mass%, (C) Component 0-50 mass% A method for producing an antifoaming composition, characterized by being mixed in step (b).