JP2000265197A - Solvent and cleansing article surface using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a solvent not causing ozone depletion, sparingly having toxicity, excellent in nonflammability, flame retardancy and thermal stability and useful for cleaning surfaces of articles or the like by including a specific fluorine-containing ketone. SOLUTION: This solvent comprises a fluorine-containing ketone expressed by the formula. It is preferable to prepare a dewatering and drying solvent comprising the fluorine-containing ketone expressed by the formula and a lower alcohol such as methanol and to remove a stain or water each adhering to the surfaces of articles such as electronic parts and optical lens. The solvent is eferably added with both (preferably 1-20 wt.%) liquid organic compound (having preferably 40-120 deg.C boiling point) such as a (fluorinated) hydrocarbon or a (fluorinated) alcohol based on the total weight of all solvents and (preferably 0.5-20 wt.%) water. The compound of the formula is a new substance and is obtained by reacting undecafluoroisocaproic acid with methylmagnesium bromide in diethyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solvent and a method for cleaning an article surface using the same.

[0002]

_2. Description of the Related Art CCl ₂ FCClF ₂ (CFC113), which is excellent in nonflammability, low toxicity and heat stability, for removing dirt and moisture such as flux and oil adhering to the surface of articles.
Also, it has been widely used to use 1,1,1-trichloroethane, a mixture of CFC113 with another solvent and the like as a detergent. In particular, the CFC 113 has a feature of selectively dissolving various kinds of dirt without invading a base material such as metal, plastic, and elastomer. It was optimal for cleaning components and optical components. Although CFC113 and 1,1,1-trichloroethane, which have been used conventionally, have various advantages, they are extremely stable chemically, so that they have a long life in the troposphere and diffuse to reach the stratosphere. Photodecomposes with ultraviolet rays to generate chlorine radicals. Since the chlorine radical causes a chain reaction with stratospheric ozone and destroys the use of ozone, its production has been banned since 1996 and regulations on consumption have been enforced.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a novel solvent which is excellent in nonflammability or flame retardancy, low toxicity and thermal stability and does not cause destruction of the ozone layer, and a method for producing an article using the same. It is an object to provide a cleaning method.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, there is provided a solvent comprising a fluorinated ketone represented by the following formula (1) or (2). nC ₄ F ₉ COC ₂ H ₅ (1) (CH ₃ ) ₂ CFCF ₂ CF ₂ COCH ₃ (2) Further, according to the present invention, a draining dry solvent comprising the fluorine-containing ketone and a lower alcohol is provided. You. Further, according to the present invention, there is provided a method for cleaning the surface of an article, comprising removing dirt or moisture adhering to the surface of the article using the solvent.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The solvent of the present invention comprises a fluorinated ketone represented by the above formula (1). Table 1 shows the physical properties of the fluorine-containing ketone.

[0006]

[Table 1]

[0007] All of these fluorine-containing ketones have low toxicity and excellent thermal stability and did not decompose even when heated for a long time with water. In addition, it was confirmed that they exhibited nonflammability or flame retardancy. Furthermore, as shown in Table 1, it was confirmed that these had physical properties particularly suitable as a cleaning solvent.

The fluorinated ketones in the present invention are all novel compounds. Of the fluorinated ketones, C
F ₃ CF ₂ CF ₂ CF ₂ COCH ₂ CH ₃ can be easily synthesized by reacting nonafluorovaleric acid (CF ₃ CF ₂ CF ₂ CF ₂ COOH) with ethylmagnesium bromide in diethyl ether. (CH ₃ ) ₂ CFC
F ₂ CF ₂ COCH ₃ can be easily synthesized by reacting undecafluoroisocaproic acid ((CH ₃ ) ₂ CFCF ₂ CF ₂ COOH) with methylmagnesium bromide in diethyl ether.

[0009] The solvent comprising the fluorinated ketone of the present invention may contain other liquid organic compounds in addition to the fluorinated ketone. The boiling point of such a liquid organic compound is
It is 300 ° C or lower, preferably 150 ° C or lower, and the lower limit of the boiling point is usually about 25 to 30 ° C. Preferably, it has a boiling point of 40 to 120 ° C. Such liquid organic compounds include hydrocarbons, fluorinated hydrocarbons,
Alcohol, fluorinated alcohol, ether, ketone,
Esters, organic nitrogen compounds, organic sulfur compounds and organosilicon compounds are included. The content of such a liquid organic compound is 1 to 50% by weight, preferably 1 to 2% by weight, based on the total solvent.
0% by weight. In the case of a flammable liquid organic compound, if the content exceeds the above range, the flammability of the solvent increases, which is not preferable. On the other hand, if the content is less than the above range, the effect of adding the compound becomes insufficient, which is not preferable.

Specific examples of the hydrocarbon include, for example,
Examples thereof include aliphatic or aromatic hydrocarbons such as pentane, hexane, heptane, octane, cyclopentane, cyclohexane, benzene, and toluene. As fluorinated hydrocarbons, HFC43-10mee (CF ₃ CF ₂
CHFCHFCF ₃ ), HFC338Pcc (CHF ₂ C
F ₂ CF ₂ CHF ₂ ). Examples of the alcohol include methanol, ethanol, propanol, isopropanol, butanol, carbitol and the like.
Examples of the fluorinated alcohol include trifluoroethanol, hexafluoro-2-propanol, pentafluoropropanol and the like. Examples of the ether include diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, monoglyme, diglyme and the like. Ketones include acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone and the like. Esters include carboxylate esters, for example, formate esters, acetate esters and the like. Examples of the organic nitrogen compound include acetonitrile, nitrobenzene, dimethylformamide, N-methylpyrrolidone and the like. Examples of the organic sulfur compound include dimethyl sulfoxide, sulfolane and the like. Examples of the organosilicon compound include tetramethylsilane, tetraethylsilane, methoxytrimethylsilane, ethoxytrimethylsilane, hexamethyldisiloxane, octamethylcyclotetrasiloxane, and the like. Preferred among these components is alcohol.

Water can be added to the solvent comprising the fluorinated ketone and the solvent comprising the fluorinated ketone and the liquid organic compound of the present invention. In this case, the amount of water is 0.01 to 50% by weight, preferably 0.5 to 2% by weight, based on the total solvent.
0% by weight. Water added to the solvent is present in the solvent in a dissolved or dispersed state, but when present in a dispersed state,
It is preferable to add a surfactant at the same time and emulsify in a solvent. The solubility of water in these fluorinated ketones is 0.01 to 10% by weight. These fluorinated ketones can be dissolved by adding water to form a solution comprising water and the fluorinated ketone. In this mixed solution, the concentration of water is at least 0.01% by weight, and the upper limit is 1%.
It is about 0 to 20% by weight. In the present invention, it is also possible to add more water and use the added water in a dispersed state. The water-containing solvent as described above has an improved effect of removing hydrophilic stains.

When the solvent of the present invention is used under severe conditions, various stabilizers may be added. As the stabilizer, a liquid compound which is entrained and discharged into the fluorinated ketone by a distillation operation or a liquid compound which forms an azeotropic or azeotropic mixture is desirable. Specific examples of such a stabilizer include aliphatic nitro compounds such as nitromethane and nitroethane; aromatic nitro compounds such as nitrobenzene and nitrostyrene; dimethoxymethane, 1,2-dimethoxyethane, 1,4-dioxane, Ethers such as 3,5-trioxane; epoxys such as chrysidol, methyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, 1,2-butylene oxide, cyclohexene oxide, epichlorohydrin; hexene, heptene, pentadiene, cyclopentene, cyclohexene Unsaturated hydrocarbons; allyl alcohol,
Olefinic alcohols such as 1-buten-3-ol; acetylenic alcohols such as 3-methyl-1-buten-3-ol and 3-methyl-1-pentene-3ol; methyl acrylate, ethyl acrylate; Acrylates such as butyl acrylate and vinyl methacrylate; In order to further obtain a synergistic stabilizing effect, phenols, amines, benzotriazoles and the like may be used in combination. The amount of the stabilizer used varies depending on the type of the stabilizer and the like, but is usually about 0.01 to 10% by weight, more preferably about 0.1 to 5% by weight in the solvent.

Various surfactants can be added to the solvent of the present invention as needed in order to further improve its detergency, interfacial action and the like. Examples of the surfactant include sorbitan fatty acid esters such as sorbitan monooleate and sorbitan triolate; polyoxyethylene sorbite fatty acid esters such as polyoxyethylene sorbite tetraoate; polyoxyethylene lauryl such as polyoxyethylene monolaurate. Ethers; polyoxyethylene alkylphenyl ethers such as polyoxyethylene noniphenyl ether; nonionic surfactants such as polyoxyethylene alkylamine fatty acid amides such as polyoxyethylene oleic acid amide;
They may be used alone or in combination of two or more. For the purpose of synergistically improving the detergency and the interfacial action, a cationic surfactant or an anionic surfactant may be used in combination with these nonionic surfactants. The total amount of the surfactant added varies depending on the type thereof, but is 0.01 to 20% by weight, preferably 0.1% by weight, in the solvent.
1 to 5% by weight.

The solvent of the present invention can be advantageously used as a cleaning agent for removing dirt and water adhering to the article surface and cleaning the article surface. The stains adhering to the article surface in this case include stains caused by flux, oil, grease, wax, ink and the like, as well as various stains removed by conventional dry cleaning. Conventionally, these stains have been removed using CFC113, 1,1,1-trichloroethane or the like.
It is advantageously applied as a substitute for CFC113 or 1,1,1-trichloroethane. The articles include electronic parts (printed circuit boards, liquid crystal displays, magnetic recording parts, semiconductor materials, etc.), electric parts, precision mechanical parts, resin processed parts, optical lenses, clothing, and the like. As a method for cleaning the surface of the article, a conventionally used method such as immersion, spraying, boiling cleaning, ultrasonic cleaning, steam cleaning or a combination thereof can be adopted.

The mixed solution comprising the fluorinated ketone and the lower alcohol according to the present invention can be advantageously used as a drainage drying solvent. As the lower alcohol, an alcohol having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, such as methanol, ethanol, isopropanol and butanol, is used, and the concentration in the solvent is 1 to 50% by weight, preferably 1 to 50% by weight.
20% by weight. The draining and drying solvent is applied to the surface of the article having water after washing with water by an appropriate method such as a spray method or an immersion method, whereby the adhering water can be removed.

The solvent comprising the fluorinated ketone of the present invention can be used as a refrigerant for refrigerators, air conditioners and the like. The solvent of the present invention can be used for various uses such as a solvent for a paint, an extractant, a heat medium and the like, like the conventional fluorocarbon.

[0017]

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

Example 1 A flux washing test was performed using the solvents shown in Table 2. Test piece (SUS-316; 50mm × 10m)
mx 1 mm) with flux [GX- manufactured by Asahi Chemical Laboratory.
8S] at 50 ° C. for 1 minute, and then take out 200
Heat treatment was performed at 1 ° C. for 1 minute. The test piece was subjected to ultrasonic cleaning in a solvent for 1 minute, and then dried with warm air. Flux removal status on the test piece (A: good, B: slightly good,
C; poor) was observed with the naked eye and a microscope, and the results are shown in Table 2.
It was shown to.

[0019]

[Table 2]

Example 2 An adhering water removal test was carried out using a mixture of 95% by weight of a fluorinated ketone and 5% by weight of an alcohol [methanol (MeOH) ethanol (EtOH) or isopropanol (iPrOH)] shown in Table 3. . A glass plate (30 mm × 20 mm × 1 mm), which had been degreased and washed well in advance, was immersed in pure water for 1 minute, and then immersed in the above mixture for 30 seconds.
The removed glass plate was allowed to stand at room temperature for 1 minute to evaporate the remaining mixture, which was then immersed in anhydrous methanol, and the increase in water content of the methanol was measured by a Karl Fischer moisture meter. On the other hand, from the comparison with the increase in water content of methanol when not immersed in the above mixture but immersed in pure water, and observation of the surface state with the naked eye and a microscope, the removal state of the attached water (A: good, B Slightly good, C;
Defective) and the results are shown in Table 3.

[0021]

[Table 3]

Example 3 Fluorine-containing ketone CF ₃ CF ₂ CF ₂ CF ₂ COCH ₂ CH
₃ 0.047 mol and 0.094 mol of water were put in a flask and refluxed at 80 ° C. for 72 hours. When the organic layer was analyzed by gas chromatography (TCD), there was no change in the composition, and Analysis by pre-test gas chromatography (TCD) showed no change in composition and no change in acidity before and after the test. From this, it was confirmed that the fluorinated ketone used in the present invention had excellent stability.

[0023]

According to the present invention, the solvent comprising a fluorinated ketone of the present invention is free from the risk of destruction of the ozone layer because the fluorinated ketone does not contain a chlorine atom.
Since it has high reactivity with hydroxyl radicals in the atmosphere and is easily decomposed in the troposphere, the greenhouse effect is small and the conventional CF
It can be advantageously used as a cleaning solvent, a draining desiccant or the like instead of C or HCFC.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 17, 2000 (2004.1.
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Solvent and method for cleaning article surface using the same

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solvent and a method for cleaning an article surface using the same.

[0002]

_2. Description of the Related Art CCl ₂ FCClF ₂ (CFC113), which is excellent in nonflammability, low toxicity and heat stability, for removing dirt and moisture such as flux and oil adhering to the surface of articles.
Also, it has been widely used to use 1,1,1-trichloroethane, a mixture of CFC113 with another solvent and the like as a detergent. In particular, the CFC 113 has a feature of selectively dissolving various kinds of dirt without invading a base material such as metal, plastic, and elastomer. It was optimal for cleaning components and optical components. Although CFC113 and 1,1,1-trichloroethane, which have been used conventionally, have various advantages, they are extremely stable chemically, so that they have a long life in the troposphere and diffuse to reach the stratosphere. Photodecomposes with ultraviolet rays to generate chlorine radicals. Since the chlorine radical causes a chain reaction with stratospheric ozone and destroys the use of ozone, its production has been banned since 1996 and regulations on consumption have been enforced.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a novel solvent which is excellent in nonflammability or flame retardancy, low toxicity and thermal stability and does not cause destruction of the ozone layer, and a method for producing an article using the same. It is an object to provide a cleaning method.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, a solvent comprising a fluorine-containing ketone represented by the following formula (1) is provided. ( CF ₃ ) ₂ CFCF ₂ CF ₂ COCH ₃ ( 1 ) Further, according to the present invention, there is provided a draining dry solvent comprising the fluorinated ketone and a lower alcohol. Further, according to the present invention, there is provided a method for cleaning the surface of an article, comprising removing dirt or moisture adhering to the surface of the article using the solvent.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The solvent of the present invention comprises a fluorinated ketone represented by the above formula (1). Table 1 shows the physical properties of the fluorine-containing ketone.

[0006]

[Table 1]

[0007] All of these fluorine-containing ketones have low toxicity and excellent thermal stability, and did not decompose even when heated for a long time with water. In addition, it was confirmed that they exhibited nonflammability or flame retardancy. Furthermore, as shown in Table 1, it was confirmed this compound are particularly has suitable properties as a cleaning solvent.

[0008] The fluorinated ketone of the present invention is a novel compound. ( CF ₃ ) ₂ CFCF ₂ CF ₂ COCH
₃ is undecafluoroisocaproic acid (( CF ₃ ) ₂ CF
(CF ₂ CF ₂ COOH) and methyl magnesium bromide can be easily synthesized by reacting the same in diethyl ether.

[0009] The solvent comprising the fluorinated ketone of the present invention may contain other liquid organic compounds in addition to the fluorinated ketone. The boiling point of such a liquid organic compound is
It is 300 ° C or lower, preferably 150 ° C or lower, and the lower limit of the boiling point is usually about 25 to 30 ° C. Preferably, it has a boiling point of 40 to 120 ° C. Such liquid organic compounds include hydrocarbons, fluorinated hydrocarbons,
Alcohol, fluorinated alcohol, ether, ketone,
Esters, organic nitrogen compounds, organic sulfur compounds and organosilicon compounds are included. The content of such a liquid organic compound is 1 to 50% by weight, preferably 1 to 2% by weight, based on the total solvent.
0% by weight. In the case of a flammable liquid organic compound, if the content exceeds the above range, the flammability of the solvent increases, which is not preferable. On the other hand, if the content is less than the above range, the effect of adding the compound becomes insufficient, which is not preferable.

Specific examples of the hydrocarbon include, for example,
Examples thereof include aliphatic or aromatic hydrocarbons such as pentane, hexane, heptane, octane, cyclopentane, cyclohexane, benzene, and toluene. As fluorinated hydrocarbons, HFC43-10mee (CF ₃ CF ₂
CHFCHFCF ₃ ), HFC338Pcc (CHF ₂ C
F ₂ CF ₂ CHF ₂ ). Examples of the alcohol include methanol, ethanol, propanol, isopropanol, butanol, carbitol and the like.
Examples of the fluorinated alcohol include trifluoroethanol, hexafluoro-2-propanol, pentafluoropropanol and the like. Examples of the ether include diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, monoglyme, diglyme and the like. Ketones include acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone and the like. Esters include carboxylate esters, for example, formate esters, acetate esters and the like. Examples of the organic nitrogen compound include acetonitrile, nitrobenzene, dimethylformamide, N-methylpyrrolidone and the like. Examples of the organic sulfur compound include dimethyl sulfoxide, sulfolane and the like. Examples of the organosilicon compound include tetramethylsilane, tetraethylsilane, methoxytrimethylsilane, ethoxytrimethylsilane, hexamethyldisiloxane, octamethylcyclotetrasiloxane, and the like. Preferred among these components is alcohol.

Water can be added to the solvent comprising the fluorinated ketone and the solvent comprising the fluorinated ketone and the liquid organic compound of the present invention. In this case, the amount of water is 0.01 to 50% by weight, preferably 0.5 to 2% by weight, based on the total solvent.
0% by weight. Water added to the solvent is present in the solvent in a dissolved or dispersed state, but when present in a dispersed state,
It is preferable to add a surfactant at the same time and emulsify in a solvent. The solubility of water in these fluorinated ketones is 0.01 to 10% by weight. These fluorinated ketones can be dissolved by adding water to form a solution comprising water and the fluorinated ketone. In this mixed solution, the concentration of water is at least 0.01% by weight, and the upper limit is 1%.
It is about 0 to 20% by weight. In the present invention, it is also possible to add more water and use the added water in a dispersed state. The water-containing solvent as described above has an improved effect of removing hydrophilic stains.

When the solvent of the present invention is used under severe conditions, various stabilizers may be added. As the stabilizer, a liquid compound which is entrained and discharged into the fluorinated ketone by a distillation operation or a liquid compound which forms an azeotropic or azeotropic mixture is desirable. Specific examples of such a stabilizer include aliphatic nitro compounds such as nitromethane and nitroethane; aromatic nitro compounds such as nitrobenzene and nitrostyrene; dimethoxymethane, 1,2-dimethoxyethane, 1,4-dioxane, Ethers such as 3,5-trioxane; epoxys such as chrysidol, methyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, 1,2-butylene oxide, cyclohexene oxide, epichlorohydrin; hexene, heptene, pentadiene, cyclopentene, cyclohexene Unsaturated hydrocarbons; allyl alcohol,
Olefinic alcohols such as 1-buten-3-ol; acetylenic alcohols such as 3-methyl-1-buten-3-ol and 3-methyl-1-pentene-3ol; methyl acrylate, ethyl acrylate; Acrylates such as butyl acrylate and vinyl methacrylate; In order to further obtain a synergistic stabilizing effect, phenols, amines, benzotriazoles and the like may be used in combination. The amount of the stabilizer used varies depending on the type of the stabilizer and the like, but is usually about 0.01 to 10% by weight, more preferably about 0.1 to 5% by weight in the solvent.

Various surfactants can be added to the solvent of the present invention as needed in order to further improve its detergency, interfacial action and the like. Examples of the surfactant include sorbitan fatty acid esters such as sorbitan monooleate and sorbitan triolate; polyoxyethylene sorbite fatty acid esters such as polyoxyethylene sorbite tetraoate; polyoxyethylene lauryl such as polyoxyethylene monolaurate. Ethers; polyoxyethylene alkylphenyl ethers such as polyoxyethylene noniphenyl ether; nonionic surfactants such as polyoxyethylene alkylamine fatty acid amides such as polyoxyethylene oleic acid amide;
They may be used alone or in combination of two or more. For the purpose of synergistically improving the detergency and the interfacial action, a cationic surfactant or an anionic surfactant may be used in combination with these nonionic surfactants. The total amount of the surfactant added varies depending on the type thereof, but is 0.01 to 20% by weight, preferably 0.1% by weight, in the solvent.
1 to 5% by weight.

The solvent of the present invention can be advantageously used as a cleaning agent for removing dirt and water adhering to the article surface and cleaning the article surface. The stains adhering to the article surface in this case include stains caused by flux, oil, grease, wax, ink and the like, as well as various stains removed by conventional dry cleaning. Conventionally, these stains have been removed using CFC113, 1,1,1-trichloroethane or the like.
It is advantageously applied as a substitute for CFC113 or 1,1,1-trichloroethane. The articles include electronic parts (printed circuit boards, liquid crystal displays, magnetic recording parts, semiconductor materials, etc.), electric parts, precision mechanical parts, resin processed parts, optical lenses, clothing, and the like. As a method for cleaning the surface of the article, a conventionally used method such as immersion, spraying, boiling cleaning, ultrasonic cleaning, steam cleaning or a combination thereof can be adopted.

The mixed solution comprising the fluorinated ketone and the lower alcohol according to the present invention can be advantageously used as a drainage drying solvent. As the lower alcohol, an alcohol having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, such as methanol, ethanol, isopropanol and butanol, is used, and the concentration in the solvent is 1 to 50% by weight, preferably 1 to 50% by weight.
20% by weight. The draining and drying solvent is applied to the surface of the article having water after washing with water by an appropriate method such as a spray method or an immersion method, whereby the adhering water can be removed.

The solvent comprising the fluorinated ketone of the present invention can be used as a refrigerant for refrigerators, air conditioners and the like. The solvent of the present invention can be used for various uses such as a solvent for a paint, an extractant, a heat medium and the like, like the conventional fluorocarbon.

[0017]

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

Example 1 A flux washing test was performed using the solvents shown in Table 2. Test piece (SUS-316; 50mm × 10m)
mx 1 mm) with flux [GX- manufactured by Asahi Chemical Laboratory.
8S] at 50 ° C. for 1 minute, and then take out 200
Heat treatment was performed at 1 ° C. for 1 minute. The test piece was subjected to ultrasonic cleaning in a solvent for 1 minute, and then dried with warm air. Flux removal status on the test piece (A: good, B: slightly good,
C; poor) was observed with the naked eye and a microscope, and the results are shown in Table 2.
It was shown to.

[0019]

[Table 2]

Example 2 An adhering water removal test was carried out using a mixture of 95% by weight of a fluorinated ketone and 5% by weight of an alcohol [methanol (MeOH) ethanol (EtOH) or isopropanol (iPrOH)] shown in Table 3. . A glass plate (30 mm × 20 mm × 1 mm), which had been degreased and washed well in advance, was immersed in pure water for 1 minute, and then immersed in the above mixture for 30 seconds.
The removed glass plate was allowed to stand at room temperature for 1 minute to evaporate the remaining mixture, which was then immersed in anhydrous methanol, and the increase in water content of the methanol was measured by a Karl Fischer moisture meter. On the other hand, from the comparison with the increase in water content of methanol when not immersed in the above mixture but immersed in pure water, and observation of the surface state with the naked eye and a microscope, the removal state of the attached water (A: good, B Slightly good, C;
Defective) and the results are shown in Table 3.

[0021]

[Table 3]

[ 0022 ]

According to the present invention, the solvent comprising a fluorinated ketone of the present invention is free from the risk of destruction of the ozone layer because the fluorinated ketone does not contain a chlorine atom.
Since it has high reactivity with hydroxyl radicals in the atmosphere and is easily decomposed in the troposphere, the greenhouse effect is small and the conventional CF
It can be advantageously used as a cleaning solvent, a draining desiccant or the like instead of C or HCFC.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Kurokawa 6F, Hongo Wakai Building, 2-40-17 Hongo, Bunkyo-ku, Tokyo New Refrigerant etc. Project Room (72) Inventor Tetsuya Suzuda Tokyo 6F, Hongo Wakai Building, Hongo 2-40-17, Hongo, Tokyo, Japan New Refrigerant Project Room (72) Inventor Junji Murata, 2-40-17 Hongo Wakai Building, Hongo, Bunkyo-ku, Tokyo Research Institute of Innovative Technology for the Environment, New Refrigerants, etc. (72) Inventor Akira Sekiya 1-1-1 Higashi, Tsukuba, Ibaraki Pref. ED30 FA03 FA21

Claims (3)

[Claims] 1. A solvent comprising a fluorinated ketone represented by the following formula (1) or (2). _{n-C 4 F 9 COC 2} H 5 (1) (CH 3) 2 CFCF 2 CF 2 COCH 3 (2) 2. A draining dry solvent comprising a fluorinated ketone represented by the following formula (1) or (2) and a lower alcohol. _{n-C 4 F 9 COC 2} H 5 (1) (CH 3) 2 CFCF 2 CF 2 COCH 3 (2) 3. A method for cleaning an article surface, comprising removing dirt or moisture adhering to the article surface using the solvent according to claim 1.