JP3100302B2 - Method for producing oil compound for antifoaming agent and antifoaming composition containing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oil compound for an antifoaming agent used in various industries and an antifoaming composition containing the same.

[0002]

2. Description of the Related Art Since silicone-based defoamers have various superior properties compared to other types of defoamers, synthetic resin industry, oil and fat industry, fermentation industry, rubber industry, food industry, petrochemical industry, It is widely used in manufacturing processes involving foaming in the textile industry, pulp and paper industry, and the pharmaceutical industry, etc. For this purpose, silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylvinylpolysiloxane are combined with fine powder silica. A mixed oil compound type antifoaming agent and an emulsion type antifoaming agent obtained by dispersing these oil compounds together with a surfactant in water are widely used. In addition, this emulsion type antifoaming agent is modified with a polyoxyalkylene group as an alternative, because under severe conditions such as high temperature, high alkalinity and high shear force, the emulsion is destroyed and the defoaming ability is reduced. Self-emulsifying defoamer using an organopolysiloxane and an oil compound in combination (JP-B-52-19836, JP-B-52-22638)
No. 55-23084), dyeing, various oils,
Used for applications such as aqueous inks.

However, these silicone-based defoamers also lose their defoaming properties over time in systems that violently come into contact with gas in a foaming liquid or systems that are vigorously stirred under heating conditions such as high-temperature dyeing. Therefore, there is a problem that it is necessary to increase the amount of the defoaming agent added or to continuously add the defoaming agent. For this reason, for this silicone-based antifoaming agent, for example, a method is used in which silica used for an oil compound is previously treated with dimethyldichlorosilane or the like to make it hydrophobic (see Japanese Patent Publication No. 52-31836). Treatment with elemental compounds
However, these methods are not economical because they require a long time for the hydrophobizing treatment of silica, require processing equipment, and have complicated processes.

There has also been proposed a composition comprising an organopolysiloxane or a hydrocarbon compound added with an organohydrogenpolysiloxane, silica and a catalyst (see JP-A-57-48307). If the catalyst is not added and heat-treated, the surface treatment of the silica will not proceed sufficiently, and there is a risk of flammable explosion due to the hydrogen gas generated during the treatment process.In addition, organopolysiloxane and silica may contain organosilicon compounds and catalyst. (Japanese Patent Publication No. 3-39722), in which a siloxane resin composed of (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units is mixed with an organopolysiloxane and silica. (Tokuhei 3
Which treats silica with a mixture of a cyclic siloxane, water and a reaction accelerator (see JP-A-6-15).
Japanese Patent No. 4513) has been proposed, but the sustained effect of these defoaming properties is not always satisfactory.

[0005]

Therefore, the inventors of the present invention have previously added an inorganic ammonium salt compound to organopolysiloxane and hydrophobized silica for the purpose of improving the defoaming continuity under high shearing force and high temperature. A method of mixing and heat-treating (see Japanese Patent Publication No. 4-42043) and an oil compound component comprising silicone oil having a branching unit and silica (see Japanese Patent Application Laid-Open No. 6-42411) have been proposed. Although an antifoaming composition having excellent defoaming sustainability can be obtained, there is a need for an antifoaming composition having low dilution, stable dilution, and long defoaming ability.

[0006]

SUMMARY OF THE INVENTION The present invention is a method for producing an oil compound for an antifoaming agent which solves the above-mentioned problems, and is represented by the general formula (1) and has a viscosity at 25 ° C. of 10 to 10:
In producing an oil compound for an antifoaming agent comprising 500,000 cSt of a hydrophobic organopolysiloxane and a fine powder silica having a specific surface area of 100 m ² / g or more by a BET method, the weight of the hydrophobic organopolysiloxane / fine powder silica The ratio
While being mixed at 80/20 to 50/50, the mixture is heat-treated at 60 to 300 ° C., and then the hydrophobic organopolysiloxane is further mixed, so that the weight ratio of the hydrophobic organopolysiloxane / fine silica powder is 99%. / 1 to 85/15, a method for producing an oil compound for an antifoaming agent. R ¹ _a SiO _{(4-a) / 2} (1) (R ¹ is one or more monovalent organic compounds selected from a hydroxyl group or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms.) Group, 1.9 ≦ a ≦ 2.4)

That is, the present inventors have conducted various studies to develop an oil compound for an antifoaming agent having an excellent antifoaming property and an excellent defoaming sustainability, and as a result, the oily compound is composed of a hydrophobic organopolysiloxane and finely divided silica. When producing an oil compound for an antifoaming agent, if heat treatment is performed in a high-viscosity state in which the silica content is higher than the final finished composition, kneading can be carried out under a higher shear condition. It has been found that the wettability of silica with siloxane is improved, the silica is maintained in a good dispersion state, and the defoaming property is maintained even under severe stirring conditions. Furthermore, when an emulsion-type antifoaming composition and a self-emulsifying-type antifoaming composition were prepared using this oil compound for a defoaming agent as a raw material, they were found to have excellent dilution stability.
According to this production method, an antifoaming composition can be easily obtained by simple high-viscosity mixing and heat treatment of the above-mentioned components, which has been widely used, and the product has significantly improved defoaming sustainability. Found that it is economical and safe. In addition, it was confirmed that the obtained oil compound for an antifoaming agent was in a well-dispersed state, and thus had low viscosity and improved workability, thereby completing the present invention.

Hereinafter, these will be described in more detail. The hydrophobic organopolysiloxane used in the method for producing an oil compound for an antifoaming agent of the present invention may be either linear or branched, and is represented by the general formula (1).

In the general formula (1), R ¹ is a hydroxyl group or a methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl group Alkyl groups such as cyclohexyl 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; 2-phenylethyl group and 2-methyl-2. An aralkyl group such as a phenylethyl group; or a chloromethyl group or a 3-chloropropyl group in which part or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with halogen atoms, cyano groups, amino groups, or the like. , 3,3,3-trifluoropropyl, cyanoethyl, 3-aminopropyl, N-β- (A Aminoethyl)-.gamma.-aminopropyl of the group monovalent hydrocarbon radical selected from such, it is preferable from the defoaming and economy over the 80 mol% are methyl groups. A in this equation is 1.9 ≦ a ≦ 2.4. Note that this may be a liquid at normal temperature, but from the viewpoint of defoaming and workability, the viscosity at 25 ° C is 10 to 500,000 c.
It is necessary to be St, and a more preferable range is 50 to 2
It is 0,000 cSt. In general, a high viscosity is preferable to maintain the defoaming property, and a low viscosity is better from the viewpoint of quick action, but if the viscosity is less than 10 cSt, it is easily dissolved in a foaming system and the defoaming property is poor, If the viscosity exceeds 500,000 cSt, the workability at the time of producing an oil compound or using the oil compound becomes poor. The value of a is correlated with the viscosity and the structure of the hydrophobic organopolysiloxane used.Assuming that the hydrophobic organopolysiloxane used is linear, the value of a is approximately 2.4 at a viscosity of 10 cSt, and the viscosity is 500,000. In the case where the hydrophobic organopolysiloxane to be used is branched, the value of a decreases as the number of branch units increases.However, in consideration of the range that can be actually used for an oil compound, the viscosity is reduced. 500,
At 000 cSt, the value of a is approximately 1.9. As described above, the range of the value of a was limited by the viscosity and the structure of the organopolysiloxane.

The finely divided silica used in the present invention may be a known silica, which may be either wet silica or dry silica, precipitated silica, silica xerogel, fumed silica, and an organic silyl group. And specifically, Aerosil [trade name of Nippon Aerosil Co., Ltd.], Nip Seal [trade name of Nippon Silica Co., Ltd.], CABOSIL [trade name of Cabot Corporation, USA], Santocell [USA] Monsanto brand name], and these have specific surface areas determined by the BET method.
It is necessary to be at least 100 m ² / g, preferably 200 m ² / g
That is all. This is because the higher the value, the better the defoaming property.

In the present invention, the composition comprising the above-mentioned hydrophobic organopolysiloxane and the finely divided silica is mixed in a weight ratio of 80/20 to 50/50, more preferably 80/20. While mixing in the range of ~ 70/30, 60 ~ 30
0 ° C for 1 to 8 hours, more preferably 100 to 180 ° C for 2 to 2 hours.
It is necessary to perform heat treatment for 5 hours. The reason why such a mixing ratio is necessary is that if the silica content is less than 20%, the effect of improving the defoaming sustainability is insufficient, and if it exceeds 50%, the viscosity increases and the fluidity during mixing decreases significantly. Heat treatment in a high-viscosity state in which the silica content is higher than the final finished composition is a cause of poor dispersion, and organopolysiloxanes can be kneaded under higher shear conditions. This is because the wettability of the silica with respect to the silica is improved, the favorable dispersion state of the silica is maintained, and the defoaming property is maintained even under severe stirring conditions. The reason for limiting to the above heating conditions is that, in the production of an oil compound for an antifoaming agent, it is necessary to mix both under heating conditions in order to chemically adsorb the oil, that is, the organopolysiloxane to the surface of the silica, Thereby, defoaming properties are exhibited. In order to further improve the defoaming property, it is preferable to mix for a long time at a temperature just below the thermal decomposition temperature of the organopolysiloxane to be used. Even so, there is no change in the effect,
Considering the thermal decomposition temperature of the organopolysiloxane to be used, the conditions of the production process, the economics, etc.
The heating conditions were set at ８8 hours, more preferably at 100-180 ° C. for 2-5 hours. The mixer used at the time of mixing is not particularly limited as long as it can uniformly stir the above composition, but a planetary mixer, a kneader and the like are suitable.

[0012] The above-mentioned stiffened composition can then be mixed with a hydrophobic organopolysiloxane to obtain the desired silica content. The weight ratio of the hydrophobic organopolysiloxane to the finely divided silica is from 99/1 to 85 / in view of its defoaming performance and water dispersibility.
It may be in the range of 15, more preferably 95/5 to 90/10
It is. This mixing may be performed during the cooling after the heat treatment or at room temperature. By stirring for 30 minutes to 2 hours, it is possible to obtain a homogeneous antifoaming agent oil compound having a viscosity of several tens to several million cSt. it can. According to this method, the desired antifoaming agent composition can maintain the strong shearing force and the antifoaming effect at a high temperature for a longer time. In the method for producing an oil compound for an antifoaming agent of the present invention,
In order to further improve the defoaming ability, high temperature characteristics, dilution stability, etc., inorganic ammonium salts, organic silicon compounds, siloxane resins, etc. are added (Japanese Patent Publication 4-4).
2043, JP-A-5-261206 and JP-A-5-261207) are optional.

The oil compound for an antifoaming agent of the present invention thus obtained may be added to the foaming system as it is, but it is mixed with an emulsifier component containing a polyoxyalkylene-modified silicone oil as a main component. By using it as a mold defoamer composition, further high temperature, high alkali,
The defoaming durability under high shearing force can be improved.

The emulsion type antifoaming composition emulsified with a surfactant may be used as appropriate according to the purpose and application. Examples of the surfactant used include sorbitan fatty acid esters and glycerin fatty acid. ester,
Propylene glycol fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether,
Examples include, but are not limited to, polyoxyalkylene polymers. Further, regarding this emulsion type antifoaming agent, a protective colloid agent at the time of emulsification, a thickener,
Methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose and other cellulose ethers, polyvinyl alcohol, sodium alginate, sucrose fatty acid esters, sodium polyacrylate, etc. may be added as a stability improver, etc. A bactericide such as sodium acid, sorbic acid, potassium sorbate, salicylic acid, benzoic acid, alkyl parahydroxybenzoates, and organic nitrogen sulfur compounds may be added.

Further, it may be used as a solution type defoamer composition dissolved or dispersed in an organic solvent such as an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, an ether solvent or an alcohol solvent, Methyl cellulose, polyvinyl alcohol, lactose, dextrin, hydrophilic fine powder silica,
It can also be used as a powdered defoamer composition adsorbed on a fine powder carrier such as starch, or a solid defoamer composition molded by mixing a surfactant at room temperature, a water-soluble wax and the like. . The appropriate addition amount of the antifoaming composition of the present invention to the foaming system depends on the type of foaming system and the conditions of use of the antifoaming agent, except for special cases, in terms of the oil compound component in the antifoaming composition. In the range of 1 to several hundred ppm.

[0016]

EXAMPLES Next, the present invention will be described with reference to examples and comparative examples of the present invention. The viscosity in the examples is a value measured at 25 ° C. Various physical properties were measured by the following methods.

(Defoaming test) 100 g of the defoamer oil compound has an average composition formula of R ² _0.1 (CH ₃ ) _2.0 SiO _0.95 [R ²
= -C ₃ H ₆ O (C ₂ H ₄ O) ₂₅ (C ₃ H ₆ O) ₂₅ C ₄ H ₉ ]
0gSt polyoxyalkylene modified silicone oil 150g
Was added thereto and uniformly mixed at room temperature with a homomixer to prepare a self-emulsifying antifoaming composition. Then, 50 g of a 1% aqueous solution of polyoxyethylene sorbitan monooleate / reodol super TW-O120 [trade name of Kao Corporation] was placed in a 150 ml glass bottle with a stopper, and 10 g of the self-emulsifying defoamer composition was added thereto. 100 μl of a 10% aqueous dispersion was added, and the mixture was set on a shaker. Immediately after addition, 2 hours, 5 hours, 10
After the time and 24 hours, the sample was shaken at 250 times / minute × 1 minute each time, and the time (second) required to complete the defoaming was measured.

(Dilution stability test) 100 g of a 10% aqueous dispersion of the self-emulsifying antifoaming composition prepared in the defoaming stability test was added to 30
The solution was placed in a 0 ml beaker and left at 25 ° C. for 24 hours, and the appearance of the solution was evaluated by visual observation according to the following criteria. …: Good emulsion with no oil floating and no silica precipitation. Δ: There is some oil floating or silica precipitation. ×: Lots of oil floating and silica sedimentation.

Example 1 Dimethylpolysiloxane.KF having a viscosity of 100 cSt as a hydrophobic organopolysiloxane
-96 [Shin-Etsu Chemical Co., Ltd. product name] 80 parts by weight, fine powder silica nip seal HD-2 [Nippon Silica Co., Ltd. product, specific surface area 300 m ² / g] 20 parts by weight in a planetary mixer While heating at 150 ° C. for 3 hours. Then, after adding 100 parts by weight of the KF-96 (viscosity 100 cSt), the mixture was uniformly mixed, and the hydrophobic organopolysiloxane / fine silica powder had a weight ratio of 90/10 and a viscosity of 420 cSt and was 420 cSt. Was prepared.

Example 2 The initial amount of dimethylpolysiloxane used was 75 parts by weight, the amount of fine silica powder was 25 parts by weight, and the amount of dimethylpolysiloxane added after the heat treatment was 150 parts.
In the same manner as in Example 1, except that the weight ratio was changed to parts by weight, the weight ratio of hydrophobic organopolysiloxane / fine silica powder was changed to
A 90/10 oil compound B for antifoaming agent having a viscosity of 250 cSt was prepared.

(Example 3) The initial amount of dimethylpolysiloxane used was 70 parts by weight, the amount of fine powdered silica was 30 parts by weight, and the amount of dimethylpolysiloxane added after the heat treatment was 300 parts.
In the same manner as in Example 1, except that the weight ratio was changed to parts by weight, the weight ratio of hydrophobic organopolysiloxane / fine silica powder was changed to
An oil compound C for antifoaming agent having a viscosity of 450 cSt was prepared at 90/10.

(Example 4) 75 parts by weight of the above-mentioned dimethylpolysiloxane KF-96 having a viscosity of 1,000 cSt as a hydrophobic organopolysiloxane, and finely divided silica aerosil 20
0 [Nippon Aerosil Co., Ltd. product name, specific surface area 200 m ² /
g] 25 parts by weight, consisting essentially of (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units as additives, with a molar ratio of (CH ₃ ) ₃ SiO _1/2 / SiO _4/2 of 0.74 Was heated at 150 ° C. for 5 hours while mixing in a kneader 15 parts by weight of siloxane resin. Next, 237.5 parts by weight of the KF-96 (100 cSt) and the KF-96
(1,000 cSt) After adding 162.5 parts by weight, mix evenly,
Oil compound D for antifoaming agent having hydrophobic organopolysiloxane / fine powder silica / siloxane resin = 95/5/3 and viscosity of 850 cSt was prepared.

Comparative Example 1 The above-mentioned dimethylpolysiloxane having a viscosity of 100 cSt was used as a hydrophobic organopolysiloxane.
Using 180 parts by weight of KF-96 and 20 parts by weight of the fine powder silica nip seal HD-2, mixing at 150 ° C. for 3 hours,
Hydrophobic organopolysiloxane / fine silica powder = 90/1
An oil compound E for antifoaming agent having a viscosity of 880 cSt was prepared.

Comparative Example 2 237.5 parts by weight of the above-mentioned KF-96 (viscosity 100 cSt) and 237.5 parts by weight of KF-96 (viscosity 1,000 cSt) as hydrophobic organopolysiloxanes, 25 parts by weight of the above-mentioned fine powder silica / Aerosil 200, The additive consists essentially of (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units, with (CH ₃ ) ₃ Si
Using 15 parts by weight of a siloxane resin having a molar ratio of O _1/2 / SiO _4/2 of 0.74, mixing at 150 ° C. for 5 hours, hydrophobic organopolysiloxane / fine powder silica / siloxane resin = 95/5
Oil compound F for defoamer with a viscosity of 1,800 cSt at / 3
Was prepared. Oil compound A for antifoaming agent obtained above
The defoaming continuity and dilution stability of Sample Nos. To F were examined by the above-mentioned measurement methods and are shown in Table 1.

[0025]

[Table 1]

[0026]

According to the present invention, since the kneading is carried out in a state where the silica content is high, the heat treatment can be performed under a high shear. Therefore, the wettability of the silica to the organopolysiloxane is improved. A good dispersion of the silica is obtained, and then the organopolysiloxane is additionally mixed,
By using the oil compound as it is or as a defoamer composition such as an emulsion defoamer composition or a self-emulsifying defoamer composition, the defoaming durability and dilution stability can be improved. Furthermore, workability is improved because the obtained oil compound has a low viscosity.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Matsusaka 1-chome, Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Satoshi Kuwata Matsui, Usui-gun, Gunma Prefecture 1-10 Tenmachi Hitomi, Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Yasuaki Hara 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP-A-8-196811 (JP, A) JP-A-7-194904 (JP, A) JP-A-6-154513 (JP, A) JP-A-3-104 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 19/04

Claims (2)

(57) [Claims] 1. A hydrophobic organopolysiloxane having a viscosity of 10 to 500,000 cSt at 25 ° C. and a fine silica powder having a specific surface area of 100 m ² / g or more by a BET method, represented by the following general formula (1). In producing the oil compound for an antifoaming agent, the hydrophobic organopolysiloxane / fine silica powder is mixed at a weight ratio of 80/20 to 50/50,
A defoaming agent characterized in that the hydrophobic organopolysiloxane is additionally mixed with the mixture and the weight ratio of the hydrophobic organopolysiloxane to the finely divided silica is from 99/1 to 85/15. Of manufacturing oil compounds for automobiles. R ¹ _a SiO _{(4-a) / 2} (1) (R ¹ is one or more monovalent organic compounds selected from a hydroxyl group or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms.) Group, 1.9 ≦ a ≦ 2.4) 2. An antifoaming composition comprising the oil compound for an antifoaming agent obtained in claim 1.