JPH09225207A - Foam inhibitor composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a compsn. having satisfactory antifoaming property and effect maintaining property by a simple and safe method at a low cost by using organopolysiloxane having a specified degree of thixotropy and specified viscosity and fine powdery silica having a specified BET specific surface area. SOLUTION: This compsn. consists of 70-99wt.%, preferably 80-95wt.% organopolysiloxane having a degree of thixotropy of 1.03-1.50, preferably about 1.05-1.30 and 10-1,000,000cP, preferably about 100-100,000cP viscosity at 25 deg.C and 1-30wt.% fine powdery silica having >=100m<2> /g, preferably about >=200m<2> /g BET specific surface area. It is produced by mixing prescribed amts. of organopolysiloxane and fine powdery silica, heat-treating the resultant mixture at a temp. between room temp. and about 200 deg.C and removing a low b.p. fraction if necessary.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silicone type antifoaming agent.

[0002]

2. Description of the Related Art Silicone antifoaming agents have various excellent properties as compared with other antifoaming agents, so that they are not accompanied by foaming in chemical industry, food industry, petroleum industry, textile industry and pharmaceutical industry. It is widely used for defoaming in the manufacturing process,
The silicone defoaming agent is an oil compound type defoaming agent in which silicone oil such as dimethyl polysiloxane, methylphenyl polysiloxane, and methyl vinyl polysiloxane is mixed with fine powder silica, and these oil compounds are mixed with a surfactant in water. Emulsion type defoaming agent dispersed in is widely used.

[0003]

When this emulsion type defoaming agent is applied to a defoaming system under severe conditions such as high temperature, high alkalinity and high shearing force, the emulsion is destroyed and the defoaming ability is lowered. As an alternative to this, a self-emulsifying defoaming agent in which an organopolysiloxane modified with a polyoxyalkylene group and an oil compound are used in combination (Japanese Patent Publication No. 52-19836, Japanese Patent Publication No. 52-22638, Japanese Patent Publication No. 55).
-23084) is used for dyeing, various oils, water-based inks, etc. However, these silicone-based defoamers also come into intimate contact with gas in a foaming liquid,
In a defoaming system that is vigorously stirred under heating conditions, such as in high-temperature dyeing processes, the defoaming property will be lost over time.As a countermeasure against this, increase the amount of defoaming agent added or continuously There were problems such as the need to add an antifoaming agent.

Therefore, regarding these silicone-based defoaming agents, for example, a method of treating silica used in an oil compound with dimethyldichlorosilane or the like in advance to make it hydrophobic (see Japanese Patent Publication No. 52-31836), the silica is nitrogen. Method of Treatment with Containing Organosilicon Compound (Japanese Patent Publication No. 51-35556)
However, these methods require a long time for the hydrophobizing treatment of silica, require investment of treatment equipment, and have complicated processes, which is not economical. there were.

As a countermeasure against these problems, there has been proposed an organopolysiloxane or a liquid hydrocarbon containing an organohydrogenpolysiloxane, silica and a catalyst (see JP-A-57-48307).
However, this has a drawback that the surface treatment of silica does not proceed sufficiently unless heat treatment is performed by adding an organometallic catalyst and hydrogen gas is generated in the treatment step, so that there is a risk of ignition and explosion. Therefore, the inventors of the present invention have previously described a defoamer composition using an oil compound in which silica is treated with an organic silicon compound having an alkenyl group for the purpose of improving the defoaming property of a self-emulsifying defoaming agent (JP 5-261206) and a foam inhibitor composition in which a siloxane resin composed of (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units is blended in an oil compound (JP-A-5-261207). However, further improvement in characteristics is required for these as well.

The foam inhibitor composition of the present invention solves various problems of these conventional defoamers. That is, the production cost is low, the production method is simple, the production process is safe, the defoaming property of the foam inhibitor composition of the product is good, and the effect persistence is good even under severe use conditions.

[0007]

Means for Solving the Problems That is, the present invention is a foam inhibitor composition which solves the problems of these conventional antifoaming agents. (A) The thixotropy α is 1.03 to 1.50 and the viscosity at 25 ° C. is 10 A foam suppressor composition comprising 70 to 99% by weight of an organopolysiloxane of 1,000,000 cP and ( ² ) 1 to 30% by weight of finely divided silica having a BET specific surface area of 100 m ² / g or more. . However, the thixotropy α was calculated by the following equation. Thixo degree α =
η ₁ / η ₂ , (where η ₁ and η ₂ are measured viscosities by a B-type rotational viscometer at 25 ° C., and η ₁ is a value obtained by measuring the rotational speed of the rotor at β rpm, and η ₂ is 2 The value measured at a rotation speed of × β rpm, provided that η ₁ and η ₂ may have different rotor types.)

The inventors of the present invention have conducted various studies to develop a foam inhibitor composition having particularly excellent defoaming properties and defoaming durability, and as a result, have found that an organopolysiloxane having a thixotropy α of 1.03 to 1.50 and finely divided The present invention has been completed by finding that a foam suppressor composition composed of powdered silica has excellent foam breaking properties and defoaming durability, and gives a large foam breaking effect even when the amount added is small. Hereinafter, the present invention will be described in detail.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The organopolysiloxane of the component (a) constituting the foam inhibitor composition of the present invention has thixotropy. The thixotropy degree α is a value indicating the thixotropy of oil, and the larger the thixotropy α, the stronger the tackiness of oil. When the thixotropy α is less than 1.03, the tackiness is weak, so the affinity between the organopolysiloxane and the finely divided silica is weak, and thus the defoaming property of the foam inhibitor composition obtained is poor, and when it exceeds 1.50. The adhesiveness is too strong, and the gelled component becomes non-uniform, resulting in insufficient mixing of the organopolysiloxane with the finely divided silica 1.
It is in the range of 03 to 1.50, preferably in the range of 1.05 to 1.30.

On the other hand, regarding the viscosity, the higher the viscosity is, the easier the dispersion of this foam inhibitor composition and the workability are. However, if the viscosity at 25 ° C. is less than 10 cP, the stability of the obtained composition is poor. When the viscosity exceeds 1,000,000 cP, the mixture with the fine powder silica becomes insufficient, and it becomes difficult to obtain a uniform composition. Therefore, the viscosity is 10-1,
It should be in the range of 000,000 cP, with a preferred range of 100-100,000 cP. In addition, in order to enhance the thixotropy of the organopolysiloxane used here, for example, in addition to the [R ₃ SiO _1/2 ] unit and the [R ₂ SiO] unit which are structural units of a general linear organopolysiloxane, [RSiO
_3/2 ] units or [SiO _4/2 ] units can be introduced. Here, R is a monovalent hydrocarbon group having 1 to 20 carbon atoms,
This may be one kind or two or more kinds. To exemplify this, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group,
Dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, and other alkyl groups; phenyl group, tolyl group, and other aryl groups; cyclopentyl group, cyclohexyl group, and other cycloalkyl groups, or part of the hydrogen atoms of these groups such as halogen atoms Can be selected from the groups substituted with. Of these, a methyl group is most preferred.

Examples of the production method of these organopolysiloxanes include (CH ₃ ) ₃ SiCl, (CH ₃ ) ₂ SiCl ₂ and (CH
₃ ) co-hydrolyze and condense SiCl ₃ or the like, or the condensation product and cyclic low-molecular siloxane are alkali metal hydroxides,
Alkali metal silanolate or tetraalkylphosphonium hydroxide, hydroxide such as tetraalkylammonium hydroxide, sulfuric acid, or in the presence of a catalyst selected from strong acid substances such as organic sulfonic acid, at room temperature or under heating, or, Organopolysiloxanes having hydroxyl groups (CH ₃ ) ₃ SiO _1/2 units and SiO ₂ units and polydiorganosiloxanes having silanol groups are heated at room temperature or in the presence of condensation catalysts such as amine catalysts and tin catalysts. It can be easily obtained by reacting under.

Constituting the suds suppressor composition of the present invention (b)
The finely divided silica as a component may be a known one, which may be either wet silica or dry silica. As these, for example, precipitated silica, silica xerogel, fumed silica, and those whose surface is treated with an organic silyl group can be used. Specific examples include Aerosil [trade name of Nippon Aerosil Co., Ltd.], Nipsil [trade name of Nippon Silica Co., Ltd.], Cabosil [trade name of Cabot Corporation of the United States], Santocel [trade name of Monsanto Company of the United States], etc. To be In order to improve the defoaming property of the suds suppressor composition, it is necessary that these have a specific surface area by the BET method of 100 m ² / g or more, and more preferably 200 m ² / g or more.

In the foam inhibitor composition of the present invention, the component (a) is
If it is less than 70% by weight, the viscosity of the suds suppressor composition is increased to deteriorate its dispersibility and workability, and if it exceeds 99% by weight, the defoaming property is deteriorated, so that it is within the range of 70 to 99% by weight. It is necessary, and preferably 80 to 95% by weight. These foam suppressor compositions are prepared by mixing a predetermined amount of the organopolysiloxane of component (a) and the finely divided silica of component (b) and heat treating at a temperature from room temperature to 200 ° C. It is manufactured by removing it.

The foam inhibitor composition of the present invention may be directly added to the target foaming system as it is, but it may be dispersed in an organic solvent, or a polyoxyalkylene-modified silicone oil and / or polyoxyalkylene polymer may be added. It can also be used as a self-emulsifying composition that is easily dispersed in water by mixing with the coalescence, or as an oil-in-water emulsifying composition with a surfactant.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. (Note that the viscosity shows the value at 25 ° C., and the measurement was made by Tokimec Co., Ltd. DVM-
A BII type viscometer was used. )

(Synthesis Example 1: Synthesis of Base Oil A) 3,000 g of water was placed in a flask having an internal volume of 5 liter equipped with a stirrer, a thermometer, a cooling tube and a dropping device, and 490 g of trimethylchlorosilane was added thereto while stirring. A mixture of 560 g of dimethyldichlorosilane and 650 g of methyltrichlorosilane,
The reaction mixture was added dropwise over 3 hours while cooling so that the temperature of the reaction mixture became 50 ° C or lower. Stir this for another 2 hours at 30 ° C,
After separating the aqueous layer (hydrochloric acid and water), add 1,700 g of 3% sodium carbonate aqueous solution to the organic layer and stir at room temperature for 2 hours, then separate and remove the aqueous layer, and leave the remaining organic layer with 70 g of anhydrous sodium sulfate. Was added, and the mixture was stirred at room temperature for 3 hours, and then filtered to obtain a colorless transparent base oil A having a viscosity of 14 cP.

(Synthesis Example 2: Synthesis of Organopolysiloxane A) In a flask having an inner volume of 500 ml equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen gas introduction pipe, 10 g of the base oil A obtained in Synthesis Example 1 and a viscosity 22 g of trimethylsilyl end-capped polydimethylsiloxane of 10 cP and 300 g of octamethylcyclotetrasiloxane were added, and the mixture was heated to 120 ° C. while agitating with nitrogen gas. To this, 0.3 g of potassium hydroxide was added, the temperature was further raised to 150 ° C., and the mixture was stirred for 4 hours, then cooled to 100 ° C., 2 g of ethylenechlorohydrin was added, and stirring was continued at 100 ° C. for 2 hours. . The obtained reaction product was heated at 160 ° C. for 2 hours under a reduced pressure of 10 mmHg to remove unreacted low molecular weight siloxane to obtain organopolysiloxane A. When the viscosity was measured, the following value was obtained, and the thixotropy α obtained from the calculation formula from this was 1.17. [Viscosity measurement result 16,000 cP (rotor No. 4: 6 rpm
); 13,700cP (rotor No.4: 12rpm)]

(Synthesis Example 3: Synthesis of Organopolysiloxane B) In Synthesis Example 2, base oil A was used as a raw material.
An organopolysiloxane B was obtained by synthesizing under the same conditions as in Synthesis Example 2 except that 25 g and octamethylcyclotetrasiloxane were changed to 308 g. When the viscosity was measured, the following values were obtained, and the thixotropy α was 1.05. [Viscosity measurement result 2,200 cP (rotor No.2: 6 rpm
); 2,100cP (rotor No.2: 12rpm)]

(Synthesis Example 4: Synthesis of Organopolysiloxane C) Organopolysiloxane C was synthesized under the same conditions as in Synthesis Example 2 except that 6 g of base oil A and 304 g of octamethylcyclotetrasiloxane were used in Synthesis Example 2. Got When the viscosity was measured, the following values were obtained, and the thixotropy α was 1.25. [Viscosity measurement result 35,000 cP (rotor No. 4: 6 rpm
); 28,000cP (rotor No.4: 12rpm)]

(Synthesis Example 5: Synthesis of Organopolysiloxane D) In Synthesis Example 2, base oil A was used as a raw material.
An organopolysiloxane D was obtained by synthesizing under the same conditions as in Synthesis Example 2 except that 200 g of 100 g octamethylcyclotetrasiloxane was used. When the viscosity was measured, the following values were obtained, and the thixotropy α was 1.02. [Viscosity measurement result 450 cP (rotor No. 1: 6 rpm);
440cP (rotor No.1: 12rpm)]

(Synthesis Example 6 Synthesis of Organopolysiloxane E) In Synthesis Example 2, base oil A was used as a raw material.
Organopolysiloxane E was obtained by the same procedure as in Synthesis Example 2 except that 5 g of trimethylsilyl end-capped polydimethylsiloxane having a viscosity of 10 cP and 311 g of octamethylcyclotetrasiloxane were used. When the viscosity was measured, the following values were obtained, and the thixotropy α was 1.57.
Met. This organopolysiloxane E was a non-uniform one containing a gel-like component. [Viscosity measurement result 72,000cP (rotor No. 4: 3 rpm
); 46,000cP (rotor No.4: 6rpm)]

(Production Example of Foam Inhibitor Composition) Synthesis Example 2,
Three kinds of organopolysiloxanes A to D obtained in 3, 4, and 5 and dimethylpolysiloxane A of the following structural formula having a thixotropy α of 1.01 as shown below were used, and further, as a fine powder silica, Aerosil 300 [Japan Using Aerosil Co., Ltd. trade name, specific surface area 300 m ² / g] and treated silica A [Aerosil 200 (above, specific surface area 200 m ² / g) treated with hexamethyldisilazane] (Table 1) Foam inhibitor compositions Nos. 1 to 10 were produced by mixing the ingredients shown in 1 above and mixing for 3 hours at 150 ° C. under a nitrogen gas stream. In addition,
90g of organopolysiloxane E to 10g of Aerosil 300
A mixture was mixed in the same manner as above, but a uniform composition was not obtained. The viscosity and structural formula of the dimethylpolysiloxane A are shown below. [Viscosity measurement result 9,800cP (rotor No.3: 6rpm
); 9,700cP (rotor No.3: 12 rpm)] average structural _{formula: (CH 3) 3 SiO -} [(CH 3) 2 SiO] 800 -Si (CH 3) 3

[0023]

[Table 1]

(Antifoaming test using anionic foaming liquid) Sodium polyoxyethylene alkyl ether sulfate / Persoft EK [trade name of NOF Corporation]
To 500 g of a 0.1% aqueous solution, 100 ppm of the foam inhibitor composition of Nos. 1 to 10 diluted to 10% with tetrahydrofuran was added,
After stirring with a juicer mixer for 30 seconds at 25 ° C., the mixture was transferred to a 1-liter graduated cylinder, and the change in foam volume (ml) with time was measured. (Defoaming test with nonionic foaming liquid) Polyoxyethylene nonylphenyl ether Emulgen 909 [trade name of Kao Corporation] 0.05% aqueous solution 500g, diluted with tetrahydrofuran to 10% of the foam No. 1-10 The inhibitor composition (100 ppm) was added, and the mixture was stirred at 25 ° C for 30 seconds with a juicer mixer and transferred to a 1-liter graduated cylinder to measure the change in foam volume (ml) with time. The above results are listed in (Table 2).

[0025]

[Table 2]

[0026]

The foam suppressor composition of the present invention is more excellent in defoaming property and its sustainability as compared with the conventional ones. Therefore, a large defoaming effect can be obtained by adding a small amount. Therefore, for manufacturing processes such as water-based cutting oil, water-based paint and ink, for various processes such as scouring process and dyeing process in the textile industry,
It is also useful for various processes such as pulp cooking process and paper making process in the paper and pulp industries, and for wastewater treatment in various industries.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshitaka Aoki, Yoshitaka Aoki, Matsuida-cho, Gunma Prefecture, Hitomi 1 10 Hitomi, Daiji 10 Shin-Etsu Chemical Co., Ltd. Silicon Electronic Materials Research Laboratory

Claims (1)

[Claims] (A) 70 to 99% by weight of organopolysiloxane having a thixotropy α of 1.03 to 1.50 and a viscosity at 25 ° C. of 10 to 1,000,000 cP, and (b) a BET specific surface area of 100 m ² / g. A suds suppressor composition comprising 1 to 30% by weight of the above finely divided silica.