JPH11197408A - Anti-foaming agent composition for high temperature organic solvent and anti-foaming method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce replacement frequency and consumption of a cleaning liquid and reduce amount of liquid replacement work so as to reduce cost by employing an antifoaming agent composition for high temperature organic solvent comprising specified weight percents of a silicone oil containing a perfluoroarlyl group represented by a particular formula, methyl isobutyl ketone and methylene chloride. SOLUTION: Twenty to sixty wt.% of methyl isobtyl ketone or a fluorohydrocarbon having a boiling point of 30 deg.C or higher is added to a silicone oil containing a prefluoroarkyl group represented by the formula (in the formula, Me represents a methyl group, n represents an integer of 4-8, and q and p represent 50-500, respectively). Further, 20-60 wt.% of a chlorine-containing solvent containing methylene chloride, chloroform, carbon tetrachloride or the like is added so as to prepare an anti-foaming agent composition for high temperature organic solven. Addition of the composition to a vapor cleaning liquid is carried out at the time when the vapor cleaning liquid starts foaming during execution of vapor cleaning or before a start of cleaning. By such a procedure, quality troubles are avoided, amount of liquid replacement work and liquid consumption can be reduced and a large cost reduction can be effected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defoamer composition for a high-temperature organic solvent such as a steam cleaning liquid and a solvent distillate, and a defoaming method using the same.

[0002]

2. Description of the Related Art Freon 11, a substance that controls ozone depletion
3,1,1,1-trichloroethane has been used as a degreasing and steam cleaning agent in a wide range of fields such as automobile parts, electric equipment parts, mechanical parts, precision equipment parts, and optical equipment parts. However, since these ozone layer depletion-regulating substances can no longer be used, methylene chloride, unrestricted fluorochlorohydrocarbon and the like have been used as substitute solvents.

[0003]

In the following, description will be made by taking methylene chloride as an example. Methylene chloride is Freon 113,
Although it is the same kind of halogenated organic solvent as 1,1,1-trichloroethane, the physical properties are different from those of the above two,
Various problems have occurred. In general, oils and fats, metal soaps, silicone compounds, metal fines, etc. are mixed and accumulated in the cleaning liquid circulated in the degreasing and steam cleaning of various metal parts, and when the steam cleaning circulating liquid becomes dirty, crab bubbles Bubbles may form. It is considered that this foaming phenomenon is caused by a difference in surface tension and vapor density of the steam cleaning liquid. Using methylene chloride as the steam cleaning solution,
Even if degreasing and steam cleaning are performed, if the circulating cleaning liquid in the steam cleaning tank becomes contaminated with oil or the like, foam is generated and crab-like foam rises in the cleaning tank, causing the degreasing and cleaning of metal parts and the like. The foam is contaminated by the foam and causes quality problems such as metal parts. When the dirt such as oils and fats is very small, the steam cleaning liquid does not foam, and the quality trouble of metal parts and the like can be avoided by replacing the steam cleaning liquid with a new liquid before foaming occurs. However, for this reason, the frequency of changing the cleaning liquid increases, and the amount of work for liquid change increases, and at the same time,
The consumption of the cleaning liquid also increases, and the cost rises.

[0004]

The present invention solves the above-mentioned problems by using a defoamer composition for a high-temperature organic solvent such as a vapor cleaning liquid, particularly a methylene chloride vapor cleaning liquid and a solvent distillate, and using the same. It provides a defoaming method. That is, the present invention provides (a) 5 to 40% by weight of a perfluoroalkyl group-containing silicone oil represented by the following general formula (Chemical Formula 2):

Embedded image Wherein Me represents a methyl group, n is an integer of 4 to 8,
p and q are each 50 to 500. ] (B) Methyl isobutyl ketone or a defoamer composition for a high-temperature organic solvent, comprising 20 to 60% by weight of a fluorochlorohydrocarbon having a boiling point of 30 ° C or higher; The present invention provides an improved defoaming method.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The silicone oil containing a perfluoroalkyl group represented by the general formula (1), which is the main component of the antifoaming composition for a high-temperature organic solvent of the present invention, is commercially available. However, those synthesized by a method as shown in Examples described later may be used. In the general formula (Chemical Formula 1), when n is 3 or less, the solubility in an organic solvent is too high and the defoaming effect is not recognized. When n is 9 or more, the solubility in an organic solvent is too poor to use, so that n The value must be an integer from 4 to 8. Further, p and q representing the necessary perfluoroalkyl group content ratio are preferably 50 to 500 for both p and q. If p is less than 50 and q is more than 500, the solubility, dispersibility, and expandability to foam of the silicone oil become poor, and the defoaming effect is not sufficiently exhibited. If q is less than 50 and p is more than 500, the decrease in surface tension is insufficient and the solubility is too large, so that the defoaming effect is not sufficiently exhibited. From the above ranges of p and q, the preferred perfluoroalkyl group content of the silicone oil in the present invention is expressed as 9 to 91 mol% in terms of mol%.
It is. The compounding amount of the component (a) in the antifoaming composition for a high-temperature organic solvent of the present invention is preferably in the range of 5 to 40% by weight, particularly preferably in the range of 10 to 30% by weight. If the content is less than 5% by weight, the addition amount of the composition increases and the defoaming effect becomes insufficient.
This is because, when the ratio exceeds 2, the composition is easily separated and the composition tends to be non-uniform.

Next, the component (b) in the antifoaming composition for a high-temperature organic solvent of the present invention will be described. The component (b) reduces the viscosity of the composition to make it easier to handle and to adjust the amount of the composition. Examples thereof include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, hexafluoroxylene, hexafluoropropylene and the like. Fluorinated organic solvent, 1,1-dichloro-1-fluoroethane, 3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1,1,2,2 2,
Fluorochlorohydrocarbon such as 3-pentafluoropropane can be used, but it is preferable to use methyl isobutyl ketone or fluorochlorohydrocarbon having a boiling point of 30 ° C. or more from the solubility of the component (a). The content of the component (b) in the antifoaming composition of the present invention is from 20 to 60.
%, Particularly preferably in the range of
It is in the range of 30-50% by weight. If the amount is less than 20% by weight, it becomes difficult to separate the composition and maintain a uniform composition, and if it exceeds 60% by weight, the amount of the composition increases, This is because the defoaming effect becomes insufficient.

Next, the component (c) of the antifoaming composition of the present invention will be described. C) The purpose of adding the component to the composition is to facilitate the adjustment of the amount added and to make the composition advantageous in terms of cost, and when the composition is flammable, to reduce the risk of ignition and to reduce the composition. In order to be able to handle it safely,
Chlorine-containing solvents such as methylene chloride, chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene can be used, but methylene chloride is preferably used in view of toxicity, environmental destruction, and influence on defoaming performance. The content of methylene chloride in the composition is preferably in the range from 20 to 60% by weight, particularly preferably in the range from 30 to 50% by weight.
This is because if it is less than 20% by weight, it is not sufficient to achieve the above-mentioned purpose of addition, and if it exceeds 60% by weight, the composition separates and it becomes difficult to maintain a uniform composition.

It is effective to use the defoamer composition of the present invention in an amount of from 5 ppm to 20 ppm of the perfluoroalkyl group-containing silicone oil of the above-mentioned component (a) based on the pure content with respect to the treatment solution. Less than 5 ppm is not sufficient, and 20
Even if it exceeds ppm, the effect does not change and it is uneconomical. In the present invention, in addition to the main components a), b) and c), it is optional to add a dispersibility improver, a dilution stabilizer and the like which do not impair the defoaming function.

The method of adding the defoamer composition for a high-temperature organic solvent of the present invention to a steam cleaning solution is carried out at the time when the steam cleaning solution starts foaming during the steam cleaning or before the start of the cleaning. When a substance is added to the steam cleaning liquid, a remarkable defoaming effect is obtained. As a result, the above-described quality troubles can be eliminated, the amount of work for liquid replacement can be reduced, the amount of cleaning liquid used can be reduced, and significant cost reduction can be achieved.

Since the boiling point of silicone oil, which is the main component of the defoamer composition for a high-temperature organic solvent of the present invention added to a steam cleaning liquid such as methylene chloride, is higher than that of methylene chloride, etc. Even when the steam cleaning liquid to which the antifoaming composition is added is heated, the main component silicone oil does not volatilize but stays in the steam bath liquid. Therefore, even when the foaming accelerating substance, such as fats and oils, metal soaps, silicone-based components, and metal fine powders, is present, it has an air bubble suppressing effect and maintains its defoaming effect.

A dimethylsiloxane-based silicone oil, which is an antifoaming agent for ordinary aqueous foaming, did not exhibit an antifoaming effect on high-temperature organic solvents. The high temperature of the defoamer composition for a high-temperature organic solvent of the present invention generally indicates 30 ° C. or higher. The effect of the antifoaming composition for a high-temperature organic solvent of the present invention is not limited to the defoaming of a steam cleaning liquid such as methylene chloride. An excellent defoaming effect can be obtained by adding to a foam system. Regarding the distillation still liquid, an excellent defoaming effect can be obtained either by adding it to the still liquid before starting distillation or by adding it to the still liquid foamed during distillation.

Next, a schematic view of a general steam cleaning apparatus is shown in FIG. 1, and an outline of degreasing of metal parts and the like and steam cleaning using methylene chloride will be described. Objects to be cleaned, such as various metal parts,
The steps of a hot tub (immersion), a cold tub (immersion), and a steam tank (steam) are sequentially conveyed, and degreasing, cleaning and precision cleaning with steam, vaporization of a cleaning liquid from the surface of parts, drying of parts, etc. In this order, the cleaning process is completed. The cleaning liquid in the steam tank is heated and boiled by the heating heater, and the generated steam rises and condenses and liquefies on the surface of the attached cooling pipe → water separator → cold bath → hot bath → steam bath Then, a liquid circulation system that overflows and recycles is formed. The flow of the cleaning liquid is indicated by → in FIG. The object to be cleaned, such as a metal part, which has been cut and has dirt such as oils and fats adhered thereto, is degreased and washed in a warm bath to remove dirt such as oils and fats, but the cleaning liquid overflows into the steam tank. . When the washing is repeatedly performed in this manner, dirt such as oils and fats gradually concentrates and accumulates in the washing liquid in the steam tank. In such a state, bubbles are generated in the vapor cleaning liquid of methylene chloride. The defoaming effect can be obtained by adding the antifoaming composition for a high-temperature organic solvent of the present invention to the foamed steam cleaning liquid.

[0013]

EXAMPLES Examples and comparative examples are described below, but the present invention is not limited to these examples. Example 1 (Synthesis of Silicone Oil A) Water 800 was placed in a 2 liter glass flask equipped with a stirrer, thermometer, and Dimroth condenser.
After charging gr, 233 gr of 2-perfluorobutylethylmethyldichlorosilane and dimethyldichlorosilane 1
A mixture of 68 gr was charged and stirred at 60 ° C. for 3 hours. After standing, the lower oil layer was separated, 20 g of sodium bicarbonate was added, and the mixture was stirred for 1 hour.
Was added and the mixture was further stirred for 30 minutes. After filtration through filter paper, 280 gr of a colorless and transparent “hydrolyzate A” was obtained. Next, 280 gr of “Hydrolysate A”, 2 gr of decamethyltetrasiloxane and 1.4 gr of trifluoromethanesulfonic acid were put into a 500 ml glass flask equipped with a stirring rod, a thermometer and a Dimroth condenser, and the mixture was stirred at 120 ° C. for 8 hours. went. Thereafter, 4 gr of sodium bicarbonate was added, and after stirring for 1 hour, 4 gr of anhydrous sodium sulfate was further added and stirred for 30 minutes. After filtration through filter paper, the following formula (Formula 3)
And a colorless and transparent “silicone oil A” was obtained.
(Me represents a methyl group)

[0014]

Embedded image

(Preparation of Antifoaming Composition 1) 2 parts by weight of methylene chloride was added to a stock solution obtained by dissolving 1 part by weight of the "silicone oil A" obtained above in 2 parts by weight of methyl isobutyl ketone (MIBK). , Diluted and dissolved to obtain (Defoamer Composition 1) of the present invention.

Example 2 (Synthesis of Silicone Oil B) In the synthesis of Example 1, 365 gr of 2-perfluorooctylethyldichlorosilane was used in place of 2-perfluorobutylethylmethyldichlorosilane, and the others were used. "Silicone oil B" represented by the following formula (Formula 4) was obtained in the same manner as in Example 1. (Me represents a methyl group)

[0017]

Embedded image

(Preparation of Antifoaming Composition 2) 1 part by weight of the “silicone oil B” obtained above was added to 2 parts by weight of dichloropentafuropropane (trade name: Asahiclean AK-225, manufactured by Asahi Glass Co., Ltd.). To the dissolved stock solution, 2 parts by weight of methylene chloride was added and diluted and dissolved to obtain (antifoaming composition 2) of the present invention.

(Comparative Example 1) When the perfluoroalkyl group is-
CF ₃ in which silicone oil [trade name: FA600
Shinetsu Chemical Industry Co., Ltd.] 1 part by weight was dissolved in 2 parts by weight of MIBK, and 2 parts by weight of methylene chloride was added to dilute and dissolve to obtain (defoamer composition 3).

Comparative Example 2 As a silicone oil, 2 parts by weight of methylene chloride was added to a stock solution obtained by dissolving 1 part by weight of polydimethylsiloxane (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) in 2 parts by weight of MIBK. It was diluted and dissolved to obtain (antifoaming composition 4).

Using the antifoaming compositions obtained in Examples 1 and 2 and Comparative Examples 1 and 2, a comparative test of the defoaming effect of the methylene chloride vapor cleaning solution was performed by the following test method. (Defoaming test method) Four 25-liter samples of methylene chloride vapor cleaning solution having the same foaming capacity in methylene chloride vapor cleaning solution were collected, and immediately defoamed the above-prepared two kinds of Example 2 and two comparative examples. (Ppm) as shown in Table 1
After the addition, the state of the foam was visually observed, and the results are shown in (Table 1).

[0022]

[Table 1]

[0023]

The use of the defoamer composition for a high-temperature organic solvent according to the present invention reduces the occurrence of troubles in the quality of various metal parts and reduces the cost of the cleaning process of the metal parts.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a steam cleaning apparatus used for explaining the effect of the defoamer composition for a high-temperature organic solvent and the defoaming method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 hot tub (degreasing tank) 2 cold tub (rinsing tank) 3 steam tank (steam washing tank) 4 cooling pipe 5 heating heater 6 water separator

Claims (2)

[Claims] 1. (a) 5 to 40% by weight of a perfluoroalkyl group-containing silicone oil represented by the following general formula [1]: Wherein Me represents a methyl group, n is an integer of 4 to 8,
p and q are each 50 to 500. An antifoaming composition for a high-temperature organic solvent, comprising (b) methyl isobutyl ketone or 20 to 60% by weight of fluorochlorohydrocarbon having a boiling point of 30 ° C. or more, and (c) 20 to 60% by weight of methylene chloride. 2. A method for defoaming a high-temperature organic solvent using the defoamer composition for a high-temperature organic solvent according to claim 1.