JP2720467B2 - Fluorosilicone defoamer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fluorosilicone-based antifoaming agent.

[Problems to be Solved by Conventional Techniques and Inventions] Silicone-based antifoaming agents have various excellent properties compared to other antifoaming agents, and thus are widely used in industrial construction methods involving foaming. These include silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylvinylpolysiloxane mixed with finely divided silica to form an oil compound, and an emulsion type in which these oil compounds are dispersed in water together with a surfactant. Is used. However, these silicone-based defoamers have an excellent defoaming effect for aqueous foaming, but have a lower surface tension than aqueous-based foams, and have an organic solvent-based defoaming agent with high silicone solubility. There is a disadvantage that the effect is extremely weak. For this reason, a method using a composition comprising dimethylpolysiloxane and a siloxane resin has been proposed as an organic solvent-based antifoaming agent, but this method does not always show an excellent antifoaming effect. Also, Japanese Patent Publication No. 35-12564 and Japanese Patent Application Laid-Open No. 62-715
No. 06 also discloses that a perfluoroalkyl group-containing organosiloxane is used as an antifoaming agent, but this is not sufficient because the perfluoroalkyl group content is insufficient.
The defoaming effect was not satisfactory. Further Japanese Patent
JP-A-62-71507 discloses a perfluoroalkyl group and -S-
It has been proposed to use an organosiloxane containing simultaneously a specific bonding group such as or -CONH- as an antifoaming agent, but this is difficult to synthesize and has a low surface tension due to the presence of the specific bonding group. As a result, an increase in the solubility and solubilization in an organic solvent were caused, and sufficient defoaming properties were not exhibited.

[Means for Solving the Problems] The present invention has been made to solve the aforementioned problems, and has a general formula [Where A is a monovalent organic group, R _f is a perfluoroalkyl group, R ¹ is an alkylene group, Q is a monovalent organic group, and n is n ≧
1, m is an integer of m ≧ 0 And a fluorosilicone-based antifoaming agent characterized by comprising a fluorosilicone represented by the formula:

In the general formula of the present invention, A and Q are monovalent organic groups, such as methyl group, ethyl group, propyl group, butyl group, dodecyl group, alkyl group such as stearyl group, cycloalkyl group such as cyclohexyl group, and vinyl group. An alkenyl group such as an allyl group, an aryl group such as a phenyl group or a tolyl group, an aralkyl group such as a 2-phenylethyl group, or a part or all of the hydrogen atoms bonded to carbon atoms of these groups, such as chlorine or fluorine. Substituted carbon such as cyanoethyl, aminopropyl, glycidoxypropyl, trifluoropropyl, nonafluorohexyl and the like substituted with a halogen atom, cyano group, amino group, hydroxyl group, carboxyl group, epoxy group, mercapto group, etc. Examples include hydrogen groups and groups such as polyethers containing heteroatoms such as oxygen, nitrogen, and sulfur in the backbone of these groups. That. Among them, those containing polyether are effective when the antifoaming agent of the present invention is applied as an emulsion to an aqueous antifoaming agent because of good emulsifiability.

In the general formula of the present invention, R _f is a perfluoroalkyl group having 1 to 21 carbon atoms, preferably 4 to 21 carbon atoms, and a particularly preferred R _f group is one having 4 carbon atoms because of its synthetic advantage. 3
The following perfluoroalkyl groups are not particularly preferable as organic solvent defoamers because the surface tension is not sufficiently reduced.

Formula R ¹ is, -CH ₂ that does not lead to solubilization for increased and an organic solvent in surface tension _{-, CH 2 2, CH 2} 3, CH 2 4, And the like, and CH _{2 2} is particularly preferable in production.

In the general formula, n is an integer of n ≧ 1, m is an integer of m ≧ 0, and R _f content It is important to satisfy

In such a case, the solubility of the defoaming agent in the organic solvent increases, and the defoaming effect decreases, which is not preferable.

The antifoaming agent of the present invention may be added to an organic solvent to be defoamed as it is, and halogenated compounds such as 1,1,2-trichlorotrifluoroethane, meta-xylene hexafluoride and 1,1,1-trichloroethane may be used. This solution may be used by dissolving about 10 to 60% by weight in a hydrocarbon solvent. The amount of the antifoaming agent of the present invention is not particularly limited, but is approximately
10 to 1000 ppm, preferably 20 to 100 ppm, is sufficiently effective.

The treatment target of the defoaming agent of the present invention includes defoaming during the production of various latexes, defoaming of various paints, adhesives, etc., dry cleaning agents, water / oil repellents, SR processing agents, antifouling agents, etc. Defoaming, defoaming of a fire extinguishing agent or a wetting agent in which a fluorine-based surfactant is dissolved, defoaming at the time of oil drilling, and the like.

The antifoaming agent of the present invention has an excellent effect on defoaming of an organic solvent in particular, but it can be made into an emulsion type like ordinary silicone oil, or can be made into an oil compound by mixing silica to form an aqueous defoaming agent. Is also applicable.

[Example] are (Synthesis Example _{1) (C 4 F 9 C} 2 H 4 SiCH 3 O) 3 331.8g, and as the terminal blocking agent _{(CH 3) 3 SiOSi (CH} 3) 3 2.26g substituted with nitrogen Into a three-necked flask. Next, 0.1
After adding 5% by weight of trifluoromethanesulfonic acid as a catalyst and reacting at 50 ° C. for 5 hours, the reaction was neutralized by adding 20 times the amount of sodium bicarbonate of the catalyst to obtain an organopolysiloxane represented by the following formula.

(Synthesis Example 2) (C ₄ F ₉ C ₂ H ₄ SiCH ₃ O) ₃ and [(CH ₃ ) ₂ SiO] ₃ and (C
H ₃ ) ₃ SiOSi (CH ₃ ) ₃ was charged into a three-necked flask and reacted in the same manner as in Synthesis Example 1, whereby the following organopolysiloxane was obtained according to the charging ratio.

(Synthesis Example 3) In a 300 ml three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, 91.9 g of a 15% by weight aqueous sodium hydroxide solution was put, and C ₈ F ₁₇ C ₂ H ₄ (CH ₃ ) was stirred. 100 g of SiCl _{2 was} added dropwise from the dropping funnel while maintaining the reaction temperature at 50 ° C. or lower.

After completion of the dropwise addition, the mixture was further stirred for 15 minutes, the organic layer was extracted with 1,1,2-trichlorotrifluoroethane, and the extract was washed with water, dried over magnesium sulfate, and then dried under reduced pressure for 1,1,2-
Trichlorotrifluoroethane is distilled off, 90 g of a colorless liquid
I got 90 g of this liquid, (CH ₃ ) ₃ SiOSi (CH ₃ ) ₃ 0.56 g,
0.9 g of a 1% by weight (CH ₃ ) ₄ N ⁺ OH ⁻ methanol solution was placed in a three-necked flask, heated to 80 to 100 ° C. under reduced pressure, stirred and polymerized for 2 hours. After the reaction, raise the temperature in the flask to 15
The temperature was raised to 0 ° C. to decompose and remove (CH ₃ ) ₄ N ⁺ OH ⁻ as a catalyst to obtain 90 g of an organosiloxane represented by the following formula.

(Synthesis Example 4) In Synthesis Example 3, C ₈ F ₁₇ C ₂ H ₄ SiCH ₃ Cl ₂ , (CH ₃ ) ₂ SiCl ₂ ,
By appropriately changing the charging ratio of (CH ₃ ) ₃ SiOSi (CH ₃ ), an organopolysiloxane represented by the following formula was obtained.

Examples and Comparative Examples (Defoaming test) 20 ml of organic solvent (toluene, perchloroethylene) and Surflon S were placed in a 100 ml internal volume measuring cylinder with a stopper.
0.51 g of -141 (a fluorosurfactant manufactured by Asahi Glass Co., Ltd.) and 50 ppm of the organopolysiloxane synthesized above were charged and the amount of foaming after shaking was examined. The results shown in Tables 1 and 2 below were obtained. .

[Effects of the Invention] Conventional silicone antifoaming agents do not sufficiently reduce the surface tension, and are effective in defoaming in an aqueous system because they dissolve in an organic solvent. There was a disadvantage that it was extremely weak. On the other hand, the antifoaming agent of the present invention has a large effect of lowering the surface tension on silicon, a perfluoroalkyl group incompatible with an organic solvent is introduced, and its siloxane unit is more than 80 mol%. As a result, the above-mentioned problems in silicone can be solved, and as can be understood from the examples, an excellent defoaming effect can be obtained in a very short time.

Claims (1)

(57) [Claims] (1) General formula [Where A is a monovalent organic group, R _f is a perfluoroalkyl group, R ¹ is an alkylene group, Q is a monovalent organic group, and n is n ≧
1, m is an integer of m ≧ 0 A fluorosilicone-based antifoaming agent comprising a fluorosilicone represented by the formula: