JPS5922611A - Antifoaming agent - Google Patents

Abstract

PURPOSE:To improve the effect of suppressing frothing by org. solvents by using a perfluoroether compd. CONSTITUTION:The perfluoroether compd. expressed by the general formula I is basically used as an effective component in the stage of suppressing frothing by org. solvents. More specifically, a mixture of, for example, 166g hexafluoropropyleneoxide, 5.7g cesium fluoride and 100ml acetonitrile is caused to polymerize and react for 48hr at -20 deg.C in an autoclave. The obtained mixture of reaction is treated with anhydrous hydrogen fluoride and is subjected to simple distillation, whereby still residue having >=200 deg.C b.p./0.5mm.Hg, that is, the acid fluoride as shown by the formula II is obtd. The acid fluoride is treated with gaseous fluorine to distillate fractionally the reaction product, whereby the fluorides expressed by the formula III and formula IV are obtd. The antifoaming agent having the effect of suppressing frothing by org. solvents is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to antifoaming agents. More specifically, it relates to an antifoaming agent that is particularly excellent in suppressing foaming caused by organic solvents.A large number of various antifoaming agents have been proposed in the past, such as (1) polydimethylsiloxane, polyphenylmethyl Silicone antifoaming products whose main components are siloxane, polypropylmethylsiloxane, etc., or those made into oil compositions such as hydrocarbon oils and polyether oils, or those made into powders with finely powdered silica, etc. agent (Japanese Patent Publication No. 47-13487, No. 42-224)
No. 55, JP-A-49-109276, JP-A No. 48
-36084 publication [), (2) Polyethylene glycol, copoly(ethylene glycol/propylene glycol) nato polyalkylene glycol C Special Publication No. 5o
(8) polyvalent metal soap (see Japanese Patent Publication No. 42-11328), (4) alkyl phosphate or alkyl phosphite (see Japanese Patent Publication No. 47-12177). Can be mentioned.

All of these are mainly aimed at defoaming of aqueous solutions and emulsions, and some are also aimed at organic solvent solutions, but their effectiveness is small. That is, although these antifoaming agents can eliminate foam caused by water/hydrocarbon surfactants, they cannot eliminate foam caused by organic solvents, which have a lower surface tension. Moreover, the effect of extinguishing organic solvent-based foams cannot be said to be particularly good even with ordinary fluorine-based surfactants having the structure shown below.

Rf-R"' Rf: lipophobic group (or hydrophobic group) R
:Lipophilic group (or hydrophilic group) The present inventor has developed a fluorine-based group that has a sufficient suppressing effect on foaming caused not only in aqueous solutions and emulsions but also in organic solvent solutions. As a result of various studies regarding the compound, the general formula (where X is a fluorine atom or a hydrogen atom, Y is a fluorine atom or a trifluoromethyl group, and m is 1
or more, generally from 1 to 5, and n being an integer from 0 or more than 1, generally from 0 to about 50) have been found to be very effective.

Such perfluoroether compounds can be prepared by initiating the reaction with at least one of hexafluoropropylene oxide and octafluoroisobutyne oxide, or with perfluoro tert-butanol, hexafluoroacetone, trifluoroacetic fluoride, carbonyl fluoride, etc. The acid fluoride of poly(perfluoroalkylene glycol) obtained by polymerization is converted into a fluoride by treating it with fluorine gas, or as a hydride by treating it with ethylene glycol and an aqueous sodium hydroxide solution. can get.

Alternatively, in the synthesis of these various poly(perfluoroether) compounds, a compound having a desired value of n can be obtained by fractionating and using the acid fluoride used as a starting material.

The value of n is generally in the range of 0 to about 50, and preferably in the range of about 1 to 50.

These poly(perfluoroether) compounds can be added to aqueous solutions or emulsions, organic solvent solutions, polymer solutions, especially paints, etc. alone or optionally mixed with silicone oil, polyethylene glycol, polyamide, etc. By adding them, excellent antifoaming effects can be obtained.

When looking at preferred poly(perfluoroether) compounds from a structural standpoint, the terminal perfluoroalkyl group is most preferably (OF,)300- group, (or,)2oyo- group, OF,,0F20- group, etc. , 0F30- group is slightly more preferable than 0F30″f!20F2〇- group, and as for the intermediate perfluoroalkylene glycol group, Y-OF is more preferable than Y-■. The one shows better defoaming effect.

Next, the present invention will be described in detail with reference to examples.

Note that each reference example describes a method for synthesizing an antifoam compound.

Reference example 1 236 parts of perfluorinated tert-butanol and 1 part of cesium carbonate
dioxane (500 m
/) under reflux for 4 hours. Thereafter, dioxane is distilled off under reduced pressure, and the residue is vacuum dried at 100°C.

To 36.79 ml of the cesium perfluoro tert-butoxide thus obtained, 84 ml of hexafluoropropylene oxide and 50 ml of anhydrous acetonitrile were added.
1 was added thereto, and a polymerization reaction was carried out at -10°C for 48 hours. The reaction mixture was treated with anhydrous hydrogen fluoride and distilled by simple distillation (boiling point 85~
The test was carried out at 120°C and 10.3 to 0.4 cylinder Hg). F-
From the measurement results of NMR spectrum and infrared absorption spectrum, it is considered that an acid fluoride having the following structure was obtained.

Reference Example 2 A mixture of 1669% hexafluoroacetone, 720% hexafluoropropylene oxide, 12,9% cesium fluoride and 1009% diethylene glycol is subjected to a polymerization reaction in an autoclave at -10°C for 48 hours. The resulting reaction mixture was treated with anhydrous hydrogen fluoride and subjected to lucid distillation (boiling point 80-98°C/0.4 BHg). From the measurement results of F-NMR spectrum and infrared absorption spectrum, it is considered that an acid fluoride having the following structure was obtained.

Reference Example 3 Trifluoroacetic acid fluoride 116'7, hexafluoropropylene oxide 370g, cesium fluoride]
, 5.5'; l and 100 g of diethylene glycol
(7) The mixture is polymerized in an autoclave at -10°C for 48 hours. The resulting reaction mixture was treated with anhydrous hydrogen fluoride and subjected to simple distillation (boiling point 96-108°C/7-8r
nmHg). From the measurement results of F-NMR spectrum and infrared absorption spectrum, it is considered that an acid fluoride having the following structure was obtained.

Reference Example 4 In Reference Example 3, trifluoroacetic acid fluorite was replaced with carbonyl fluoride 669% (fractionated simple distillate (boiling point 142-163°C)).
Based on the measurement results of NMR spectrum and infrared absorption spectrum, it is considered to be an acid fluoride with the following structure.

Reference Example 5 Octafluoroisobutyne oxide 216'7, cesium fluoride 14.2 g and tetraethylene chloride 1
A mixture of 100 ml of 3-col dimethyl ether is subjected to a polymerization reaction at -10 DEG C. for 48 hours in an autoclave. The resulting reaction mixture was treated with anhydrous 7-day hydrogen, and
Simple distillation (boiling point 91-107℃ 10,4 tram Hg
) was carried out.

From the measurement results of the F-NMR spectrum and the Red Sun absorption spectrum, it is considered to be an acid fluoride with the following structure.

Reference Example 6 Hexafluoropropylene oxide 1669, cesium fluoride 5.7 g and acetonide I) 100 td
The mixture was subjected to a polymerization reaction in an autoclave at -20°C for 48 hours. The resulting reaction mixture was treated with anhydrous hydrogen fluoride and subjected to simple distillation to achieve a boiling point of 200°C or higher.
Q. Residue of 5 tran Hg was obtained. II'-N
Based on the MR spectrum and infrared absorption spectrum, it is considered to be an acid fluoride with the following structure.

Reference Example 7 The acid fluoride ■ obtained in Reference Example 6 was
The reaction product was treated with fluorine gas according to the method described in No. 2197, and the reaction product was fractionally distilled to obtain fluorinated products 1 and 2 represented by the following formulas.

F5 Reference Example 8 The acid fluoride obtained in Reference Example 6 was added to the special number ■39-
The reaction product was treated with ethylene glycol and an aqueous sodium hydroxide solution in accordance with the method described in Japanese Patent No. 24872, and then the reaction product was fractionally distilled to obtain hydrides I and σ■ represented by the following formulas.

Example 1 Perfluorooctylethyl acrylate 1] Rate-2-ethylhexyl acrylate (ffijA ratio 70:30
) Dilute the copolymer with 10% methyl chloroform monochloroethylene to a concentration of 0.5%, and dilute the solution 107!
into a stoppered test tube with a capacity of 25 ml.

Then, the compounds of each of the above-mentioned reference examples were added at 0.00% to the copolymer.
Add 0.5% by weight as an antifoaming agent, shake vigorously ]-0 times, and immediately and 60 seconds later measure the volume of the foam in a cylindrical test tube with a diameter of 20 mm to 0.5 units. ) was measured to evaluate its defoaming effect. The results obtained are shown in Table 1 below. Note that A5 to A9 are comparative examples.

Table 1 Anti-foaming agent Direct foam height +
m) Foam height after 60 seconds-1 Fluoride I
3.0 1.02
1/11 2.53 Hydride I 4 tt n 3. .

5 None 15.0 13.0
(i 08F',,0OONH49,07,0708
F,,0H20H20+0H20H20 Glaze H〃8 Poly(ethylene/Boohi° Leno Glycol) 15.0
13. .

9 Silicone oil Example 2 Silicone varnish for electrical insulation (Shin-Etsu Chemical KR-255
A 5% toluene solution of ) was placed in a test tube with a stopper, and the same defoaming effect test as in Example 1 was conducted. The results obtained are shown in Table 2 below. Note that A5 to A7 are comparative examples.

Table 2 1 Fluoride I 3.0
2.02 p l
2.53 Hydride 11.5 4 ttfJ 3.5
2.55 o8h,,an2aH,,of-OH
,,oH2oiH9,07,06 poly(ethylene/U5
Pyrene glycol) 15.0
15.07 Silicone oil, Example 3 Acrylic emulsion 1114 (emulsified copolymer mainly composed of ethyl acrylate with 7 anion and anion surfactants) was mixed with water to a solid content concentration of about 10%. The antifoaming effect test was carried out in the same manner as in Example 1 by diluting the solution and placing it in a stoppered test tube. The results obtained are
It is shown in Table 3 below. Note that A3 to A7 are comparative examples.

Table 3: Foam height immediately after antifoaming agent ωwa Foam height after 60 seconds -1 Fluoride 1
5.0 3.02 Hydride 1
5.5 3.53 None
15.0 14.04 08F,,
0OOON)(,9,Q 7.Q5
08F,,0H20H,,O+0H20H207//
6.06 Poly(ethylene/ub)
hileno glycol) 13,0
10.07 Silicone oil 10
．． 0 8.0 Example 4 A 5% solution of polyurethane in dimethylformamide was placed in a test tube with a stopper, and the same defoaming effect test as in Example 1 was conducted. The results obtained are shown in Table 4 below. In addition, A3
-7 are comparative examples.

Table 4 2 Hydride 1 8.0 5.
07 Silicon Oil Agent Patent Attorney Yoshi 1) Toshio

Claims (1)

[Claims] 1. General formula (where X is a fluorine atom or a hydrogen atom, Y is a fluorine atom or a fluoromethyl group, m is an integer of 1 or more, and n is An antifoaming agent containing a perfluoroether compound represented by O or an integer of 1 or more as an active ingredient.