JP2001300446A - Method for cleaning object to be cleaned - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cleaning an object to be cleaned which improves cleanability, does not cause the composition change of each detergent and a rinsing detergent, facilitates the control of a cleaning solution, and reduces the loss of the cleaning solution to reduce the running cost when the object is cleaned by a hydrocarbon containing an additive and rinsed by a cyclic fluorohydrocarbon solvent. SOLUTION: The method includes the first cleaning process for cleaning the object by the first detergent containing the additive and a hydrocarbon, the second cleaning process for rinsing the object to which the detergent is adhered by using a hydrocarbon, and the third cleaning process for making the rinsed object contact the second detergent containing a cyclic fluorohydrocarbon or an organic solvent and the cyclic fluorohydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal, glass, plastics or the like having oils, fats, greases, fluxes, hand marks, etc. adhered to the surface thereof in the precision machine industry, the optical machine industry, the electronic industry, the plastic industry, and the like. And a method for cleaning an object to be cleaned.

[0002]

2. Description of the Related Art Conventionally, non-flammable, low-toxic and stable fluorocarbons have been used as industrial cleaning methods for various materials.
One-liquid washing has been performed with trichloroethane and the like.

However, for the purpose of protecting the ozone layer, an alternative cleaning method has been proposed. As one of such cleaning methods, a cleaning method using a cyclic fluorinated hydrocarbon-based solvent is known.

(1) Japanese Patent Application Laid-Open No. 4-25598 discloses that
Formula _{C 5 H 10-n F n} (n represents. An integer of 5-8) describes a cleaning solvent comprising a fluorinated cyclopentane represented by. (2) WO 97/45521 discloses that a cleaning step of bringing a cleaning object into contact with a cleaning solvent containing hydrocarbon as a main component, and that the cleaning object to which the cleaning solvent taken out from the cleaning step adheres is larger than hydrogen atoms. A method for cleaning an object to be cleaned, comprising a rinsing step of contacting with a rinsing solvent containing a fluorine-containing, unbranched alicyclic hydrofluorocarbon having 4 to 10 carbon atoms as a main component. (3) JP-A-10-71372 discloses that an object to be cleaned is brought into contact with a cleaning solvent containing a hydrocarbon as a main component, and then the object to be cleaned attached with the hydrocarbon is rinsed with a fluorinated solvent as a main component. What is claimed is: 1. A cleaning method in which a high-purity fluorinated solvent is supplied to a rinsing bath, and the rinsing bath is uniformly maintained so as not to cause phase separation, in a cleaning method of rinsing and rinsing by immersing in a cleaning bath. Is described. (4) Also, JP-A-10-71373 discloses that an object to be cleaned is brought into contact with a cleaning solvent containing a silicone-based cleaning agent as a main component, and then the object to be cleaned to which the silicone-based cleaning agent is attached is mainly made of hydrofluorocarbon. In a cleaning method of rinsing by immersing in a rinse bath as a component, supplying high-purity hydrofluorocarbon to the rinse bath,
A method for cleaning an object to be cleaned, characterized in that the rinse bath is maintained uniformly so as not to cause phase separation. (5) Further, JP-A-10-316598 discloses that
Formula (a): Rf1-R1-Rf2 (R1 is CHF and C
H ₂ and represents a carbon ring bonded, Rf1 and Rf2 are each a perfluoroalkyl group, Rf1 and Rf2 may be bonded to each other to form a ring. A) a cleaning agent containing a fluorinated hydrocarbon or trihydrofluorocarbon having a purity of 95% by weight or more, and an article to which contaminants are adhered is contacted with an organic solvent such as hydrocarbons. It describes a process of removing contaminants, and a method of rinsing or steam-cleaning an article to which an organic solvent has adhered, with the above-mentioned cleaning agent.

[0005] As described above, the cyclic fluorinated hydrocarbon-based solvent has a property that it is poorly compatible with a general organic solvent at around room temperature and is completely compatible at around the boiling point. After washing with hydrocarbons, liquid replacement and washing (steam washing) is performed on the cyclic fluorocarbon solvent,
Good cleaning can be achieved without any hydrocarbon remaining on the object to be cleaned, and the cyclic fluorinated hydrocarbon can be reused by a cooling specific gravity separation method or the like.

[0006]

By the way, in the conventional cleaning method of cleaning with a hydrocarbon and rinsing with a cyclic fluorinated hydrocarbon solvent, the dirt is completely removed when the cleaning is performed only with the hydrocarbon. Generally, a cleaning agent obtained by adding an additive to hydrocarbon is used.

[0007] However, in this case, it is possible to completely remove the dirt from the object to be cleaned. However, when the cleaning agent attached to the object to be cleaned is replaced with a cyclic fluorocarbon solvent, the additive component is removed. Was dissolved in the cyclic fluorinated hydrocarbon solvent, and the content of the additive component in the cleaning agent collected by the cooling specific gravity separation method was sometimes changed. In addition, the additive component accumulates in the cyclic fluorocarbon-based solvent, and the cleaning ability during steam cleaning is reduced. In some cases, the separability from the agent was reduced.

[0008] Further, a solvent obtained by adding an organic solvent to a cyclic fluorinated hydrocarbon solvent may be used as a rinse detergent. In this case, the additive in the detergent (hydrocarbon containing additive) is used. Due to the presence, the organic solvent in the cyclic fluorinated hydrocarbon solvent dissolves in the cleaning agent, and there is a problem that the composition of the rinse cleaning agent is changed.

Accordingly, the present invention provides a method for cleaning an object to be cleaned in which the object to be cleaned is washed with a hydrocarbon containing an additive and rinsed with a cyclic fluorocarbon-based solvent. It is another object of the present invention to provide a method for cleaning an object to be cleaned which does not cause a change in the composition of a rinse cleaning agent, facilitates the management of the cleaning liquid, and reduces the loss of the cleaning liquid to reduce the running cost.

[0010]

In order to solve the above-mentioned problems, the present invention provides a first cleaning step of cleaning an object to be cleaned with a first cleaning agent containing an additive and a hydrocarbon; A second cleaning step of rinsing the object to be cleaned to which the agent has adhered using a hydrocarbon, and a cleaning step of rinsing the object to be cleaned using the hydrocarbon to obtain a cyclic fluorocarbon or an organic solvent and a cyclic fluorocarbon; Provided is a method for cleaning an object to be cleaned, the method including a third cleaning step of bringing the substrate into contact with a second cleaning agent containing hydrogen.

In the present invention, it is preferable that at least one selected from the group consisting of a polar solvent, a surfactant and a stabilizer is used as the additive, and the cyclic fluorohydrocarbon has a purity of 95% by weight. % Or more carbon number 4
It is preferable to use from 6 to 6 trihydrofluorocarbons. In the present invention, it is preferable to use an organic solvent having a boiling point of 25 to 300 ° C. as the organic solvent.

The present invention relates to a method for cleaning an object to be cleaned by cleaning the object to be cleaned with a hydrocarbon containing an additive and rinsing with a cyclic fluorinated hydrocarbon-based solvent. In addition, the composition of the rinse agent is not changed, the cleaning liquid can be easily managed, and the loss of the cleaning liquid can be reduced to reduce the running cost.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The cleaning method of the present invention is useful for cleaning articles (objects to be cleaned) to which contaminants have adhered. Hereinafter, the present invention will be described in detail.

(1) Object to be Washed There is no particular limitation on the object to be washed. For example, metals, ceramics, glass, metals, and the like in the precision machine industry, the metal processing industry, the optical machine industry, the electronic industry, the plastic industry, and the like.
Examples include processed products such as plastics and elastomers. Specifically, automotive parts such as bumpers, gears, transmission parts, radiator parts, printed circuit boards, IC parts, lead frames, motor parts, electronic and electrical parts such as capacitors, bearings, gears, engineering plastic gears, clock parts, cameras Parts, precision machine parts such as optical lenses, printing machines, printing machine blades, printing rolls, rolling products, construction machinery, large machine parts such as heavy machinery parts,
Household items such as tableware are subject to washing.

The types of contaminants (to be cleaned) include, for example, cutting oil, quenching oil, rolling oil, lubricating oil,
Oils such as machine oils, press working oils, punching oils, assembly oils, drawing oils, greases, wax oils, adhesives, oils and fats, mold release agents at the time of molding, hand grit, flux after soldering, solder paste, etc. Is mentioned.

(2) Cleaning Step The cleaning method of the present invention has a first cleaning step, a second cleaning step, and a third cleaning step. In the first cleaning step,
The object to be cleaned is cleaned with a cleaning agent containing an additive and a hydrocarbon.

The hydrocarbon used in the first washing step includes, for example, aliphatic hydrocarbons such as chain saturated, chain unsaturated, cyclic saturated, and cyclic unsaturated, and aromatic hydrocarbons. . The number of carbon atoms of the hydrocarbon may be appropriately selected depending on the purpose of cleaning, but is usually 5 to 30, preferably 8 to 20, and more preferably 10 to 15.

Specific examples of such hydrocarbons include pentane, hexane, heptane, octane, isooctane, nonane, decane, isodecane, undecane, dodecane, isododecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane and isooctadecane. Chain-saturated aliphatic hydrocarbons, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cyclodecane, methylcyclodecane, cyclic saturated hydrocarbons such as cyclododecane, decalin, norbornane, heptene, heptadiene, octene, octadiene, nonene , Nonadiene, decene, decadiene, undecene, dodecene, dodecadiene, nonen, nonadiene, decene, decadiene, undecene, dodecene, dodekadiene, Ridesen, tridecadiene,
Chain-unsaturated hydrocarbons such as tetradecene, tetradecadiene, octadecene, octadecadiene, isoprene dimer, α-pinene, β-pinene, γ-terpinene,
cyclic unsaturated hydrocarbons such as δ-3-carene, limonene, dipentene, and terpinene nanoterpenes; and aromatic hydrocarbons such as toluene and xylene.

Of these, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, limonene, dipentene and the like are preferred. These hydrocarbons can be used alone or in combination of two or more.

In the present invention, a commercially available hydrocarbon-based cleaning agent can be used. Commercially available hydrocarbon-based detergents include, for example, normal paraffin series, isozole series, and isozolan series (manufactured by Nippon Petrochemical Co., Ltd.), No. 0-5 solvent, and teclean series (manufactured by Nippon Petrochemical Co., Ltd.). Ishi Mitsubishi Corporation
Manufactured), NS Clean Series (manufactured by Nippon Petrochemical Co., Ltd.)
Etc. can be used.

As the additive, it is preferable to use at least one selected from the group consisting of a polar solvent, a surfactant and a stabilizer. The content of the additive is usually 1 to 99% by weight, preferably 5 to 95% by weight,
More preferably, it is 10 to 90% by weight.

Examples of the polar solvent include alcohols, ethers, glycols, sulfoxides, glycol ethers, esters, ketones, amides, and the like.
Examples include ureas, phenols, nitriles, and heterocyclic compounds.

As alcohols, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-
Examples thereof include butyl alcohol, isobutyl alcohol, t-butyl alcohol, n-pentyl alcohol, isopentyl alcohol, n-hexyl alcohol, isohexyl alcohol, 2-ethylhexyl alcohol, and n-octyl alcohol.

As ethers, diethyl ether,
Examples include dipropyl ether, diisopropyl ether, tetrahydrofuran, 1,2-dimethoxyethane, dioxane and the like. Glycols include ethylene glycol, propylene glycol and the like. Examples of the sulfoxides include dimethyl sulfoxide, diethyl sulfoxide and the like. Examples of glycol ethers include 3-methyl-3-methoxybutanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), and the like.

Esters include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate,
Isobutyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isopropyl propionate,
Examples include methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, methyl valerate, ethyl valerate and the like.

Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of the amide include N, N-dimethylformamide, N, N-dimethylacetamide and the like.

The ureas include 1,3-dimethyl-2
-Imidazolinone, N, N'-dimethylpropylene urea, 1,1,3,3-tetramethyl urea and the like. Examples of phenols include phenol, p-chlorophenol, o-cresol, m-cresol, p-cresol and the like.

The nitriles include acetonitrile, benzonitrile and the like. Examples of the heterocyclic compound include pyridine, N-methylpyrrolidone, and the like. These polar solvents can be used alone or in combination of two or more.

As the surfactant, known anionic surfactants, cationic surfactants, nonionic surfactants and amphoteric surfactants can be used. Examples of the anionic surfactant include a carboxylate, a sulfonate, a sulfate, and a phosphate. Examples of the cationic surfactant include a salt of an amine with various acids and a quaternary ammonium salt. Examples of the nonionic surfactant include polyoxyethylene ethers, polyoxyethylene-polyoxypropylene glycol, polyoxyethylene-polyoxypropylene alkyl ether, and fatty acid partial esters of polyhydric alcohols. Examples of the amphoteric surfactant include betaines, amino organic acids, and amine salts of fatty acids.

Further, surfactants containing fluorine atoms in the molecules of these compounds (fluorine surfactants) are also suitable. By adding these surfactants, it is possible to effectively remove deposits after washing with water on processed parts such as metals, ceramics, glass, plastics, and elastomers.

Examples of the stabilizer include aliphatic nitro compounds such as nitromethane and nitroethane; acetylene alcohols such as 3-methyl-1-butyn-3-ol and 3-methyl-1-pentyn-3-ol; Epoxides such as glycidol, methyl glycidyl ether, ethyl glycidyl ether, dimethoxymethane,
Ethers such as 3-dimethoxyethane and 1,4-dioxane, unsaturated hydrocarbons such as hexene, heptene, cyclopentene and cyclohexene, allyl alcohol;
Examples thereof include unsaturated alcohols such as 1-buten-3-ol and the like, and acrylates such as methyl acrylate and ethyl acrylate.

As a cleaning method, an object to be cleaned and the above-mentioned cleaning agent may be brought into contact, and a normal cleaning method can be employed.
Specific examples include methods such as hand wiping, dipping, spraying, and showering, and the dipping method is particularly preferable. In addition, when processing by immersion, ultrasonic shaking, shaking, stirring,
Physical means such as brushing can also be used in combination. The washing temperature is appropriately selected depending on the type and size of the object to be washed, the size and the type and degree of dirt, but is usually in the temperature range from room temperature to the boiling point, preferably in the temperature range from 35 ° C. to the boiling point, more preferably. The temperature range is 35 ° C to 45 ° C.

In the present invention, after the first cleaning step, the object to be cleaned to which the cleaning agent has adhered is rinsed using a hydrocarbon. Rinsing can be performed by immersing the object to be cleaned in a hydrocarbon. In addition, in order to improve the effect of rinsing, cleaning,
It is preferable to perform liquid replacement.

The hydrocarbons that can be used in the second cleaning step include the same hydrocarbons as those listed in the first cleaning step. The hydrocarbon that can be used in the second cleaning step may be the same as or different from the hydrocarbon used in the first cleaning step. It is preferable from the viewpoint of easiness of recovery.

The present invention is characterized in that, in addition to the conventional cleaning method, a step of rinsing an object to be cleaned with a hydrocarbon is provided. By newly providing this step, when the cleaning agent adhering to the object to be cleaned has been replaced with a cyclic fluorocarbon solvent, which has been a problem in the past, the additive component dissolves in the cyclic fluorocarbon solvent, The problem that the content of the additive component in the cleaning agent recovered by the cooling specific gravity separation method changes,
The additive component accumulates in the fluorocarbon-based solvent, which reduces the cleaning ability during steam cleaning or separates the fluorocarbon-based solvent in which the additive has been dissolved from the cleaning agent when separating by cooling specific gravity. In the case where a solvent obtained by adding an organic solvent to a cyclic fluorocarbon solvent is used as a rinse detergent, the presence of additives in the detergent (hydrocarbon containing additives) It is possible to prevent the problem that the organic solvent in the cyclic fluorocarbon solvent dissolves in the cleaning agent and changes the composition of the rinse cleaning agent.

Finally, the object to be cleaned, which has been rinsed with a hydrocarbon, is brought into contact with a cyclic fluorinated hydrocarbon or a second cleaning agent containing an organic solvent and a cyclic fluorinated hydrocarbon (third cleaning step). .

As the second cleaning agent, the use of cyclic fluorocarbon or cyclic fluorocarbon as a main component makes it possible to improve the rinsing ability of hydrocarbons as compared with the case where chain hydrofluorocarbon or perfluorocarbon is used. It is much better. In particular, the difference in the effects is more remarkable when the object to be cleaned is continuously cleaned.

Cyclic fluorinated hydrocarbons are generally nonflammable, have excellent stability in the presence of alkali or water, and can be used as a detergent for the surface of articles. The solubility of the hydrocarbon in the cyclic fluorinated hydrocarbon increases sharply by heating. In addition, cyclic fluorinated hydrocarbons generally have a higher boiling point than chain fluorinated hydrocarbons having the same carbon number in many cases, so that rinsing can be performed at a higher temperature, and the solubility of hydrocarbons is further improved. Can be done. On the other hand, at low temperatures (lower than the boiling point), it is incompatible with hydrocarbons, and thus the hydrocarbons washed from the object to be washed are separated into two layers above the second cleaning agent. In addition, hydrocarbons and cyclic fluorinated hydrocarbons can be easily separated, purified and reused.

The cyclic fluorinated hydrocarbon has a purity of 95.
The trihydrofluorocarbon having 4 to 6 carbon atoms by weight or more is preferable because the solubility at the time of washing and the solubility at the time of separation of two layers are balanced.

Specific examples of the trihydrofluorocarbon having 4 to 6 carbon atoms include 1,1,2,3,4-pentafluorocyclobutane, 1,1,2,2,3-pentafluorocyclobutane and 1,1 , 2,2,3,3,4
-Heptafluorocyclopentane, 1,1,2,2
3,4,5-heptafluorocyclopentane, 1,1,
2,3,3,4,5-heptafluorocyclopentane,
1,1,2,2,3,3,4,4,5-nonafluorocyclohexane, 1,1,2,2,3,4,4,5,5-
Nonafluorocyclohexane, 1,1,2,2,3
3,4,5,6-nonafluorocyclohexane, 1,
1,2,3,3,4,5,5,6-nonafluorocyclohexane and the like.

Of these, 1,1,2,2,3-pentafluorocyclobutane, 1,1,2,2,3,3,4
-Heptafluorocyclopentane, 1,1,2,2
3,3,4,4,5-Nonafluorocyclohexane is preferred, and 1,1,2,2,3,3,4-heptafluorocyclopentane is particularly preferred.

As the second cleaning agent used in the present invention, a cyclic fluorinated hydrocarbon alone or a combination of a cyclic fluorinated hydrocarbon and an organic solvent can be used.

As the organic solvent to be added to the cyclic fluorinated hydrocarbon, an organic solvent having a boiling point of 25 to 300 ° C. is preferable.
As the organic solvent, those having a small change in composition when contacted with a hydrocarbon (that is, having the same solubility as a cyclic fluorinated hydrocarbon) and having a small change in the composition of a cleaning solution even after distillation and regeneration. Is preferred. When a cyclic fluorinated hydrocarbon and an organic solvent form an azeotropic composition, use near the azeotropic composition is desirable.

As such an organic solvent, those used as ordinary rinsing solvents can be used. For example, linear saturated hydrocarbons such as hexane, octane and isooctane, cyclic saturated hydrocarbons such as cyclopentane and cyclohexane, lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and isopropyl alcohol, acetone and methyl ethyl ketone Ketones such as methyl isopropyl ketone, methyl isobutyl ketone and diethyl ketone; ethers such as dimethyl ether and diethyl ether; esters such as ethyl acetate and vinyl acetate;
Examples include chain hydrofluorocarbons such as 2,3,4,5,5,5-decafluoropentane, and perfluorocarbons such as perfluorohexane and perfluoroheptane. These organic solvents can be used alone or in combination of two or more.

When 1,1,2,2,3,3,4-heptafluorocyclopentane is used as the cyclic fluorinated hydrocarbon, ketones such as methyl ethyl ketone, methyl isobutyl ketone and diethyl ketone are used. The use of organic solvents is particularly preferred.

The method of bringing the object to be cleaned into contact with the second cleaning agent includes, for example, hand wiping, dipping, spraying, showering, steam cleaning and the like. In the treatment by immersion, physical means such as ultrasonic shaking, rocking, and stirring brushing can be used together. These contact methods can be used alone or in combination of two or more thereof.

Of these, immersion or steam cleaning is preferable, and in order to improve the finish of the object to be cleaned,
It is more preferable to use both immersion and steam cleaning.

The temperature at which the object to be cleaned is brought into contact with the second cleaning agent is appropriately selected according to the cleanliness of the object to be cleaned, but is usually in the temperature range from room temperature to the boiling point, preferably from 40 ° C. to the boiling point. Temperature range.

While the second cleaning agent is used repeatedly, hydrocarbons are concentrated in the cleaning agent, and the rinsing cleaning ability is reduced. Therefore, it is necessary to remove the hydrocarbons to be concentrated. As a removing method, a two-layer separation method or a distillation separation method is employed.

When the two-layer separation method is used, there is a specific gravity difference between the hydrocarbon used in the second washing step and the cyclic fluorinated hydrocarbon used in the third washing step. Separated into lower layers of fluorohydrocarbons. The removal of hydrocarbons can also be performed by adding fresh cyclic fluorinated hydrocarbons in the same vessel to overflow and remove the upper hydrocarbon layer.However, a part of the second cleaning liquid is transferred to another vessel,
Therefore, a method of separating the hydrocarbon layer and the cyclic fluorinated hydrocarbon layer into two layers, collecting the lower cyclic fluorinated hydrocarbon layer, and returning the layer to the second cleaning liquid is suitably performed. In the two-layer separation, a centrifugal separation method can also be used. Further, when the separation by two-layer separation is insufficient, it is also preferable to improve the purity of the collected detergent by combining multi-stage distillation or the like.

The cyclic fluorinated hydrocarbon has a high temperature (around the boiling point).
Has high solubility in hydrocarbons, but has the property of hardly dissolving hydrocarbons at low temperatures. Therefore, the operation of the two-layer separation is preferably performed at a lower temperature,
It is suitable to carry out the washing at a temperature of usually 10 ° C. or lower, preferably 20 ° C. or lower, more preferably 30 ° C. or lower.
The minimum temperature of the two-layer separation operation is preferably equal to or higher than the melting point of the hydrocarbon or cyclic fluorinated hydrocarbon.

The method for cooling the second cleaning agent is as follows.
There is no particular limitation, and any method such as a method of leaving at room temperature and cooling with a refrigerant or a method of evaporating cyclic fluorohydrocarbons and cooling with the heat of evaporation can be employed. Although there is no limitation on the cooling rate, aggressive cooling methods such as cooling from the outside and cooling by the heat of evaporation of the cyclic hydrocarbon are recommended from the viewpoint of work efficiency and prevention of loss of the cleaning liquid due to spontaneous evaporation. .

The cyclic fluorinated hydrocarbon layer recovered by the two-layer separation may be used as it is or, if necessary, may be subjected to a treatment such as distillation, filtration, activated carbon treatment, or drying. It can be reused as a cleaning agent.

The present invention can be carried out using, for example, the cleaning apparatus shown in FIG. The cleaning device shown in FIG.
Cleaning tanks 1 and 4 equipped with a heating device 10;
And washing tanks 2 and 3 equipped with an ultrasonic generator 11, and washing tanks 5, a heating apparatus 10, an ultrasonic generator 11, a steam generating tank 7, an overflow tank 8, and a single tank washing equipped with a separation tank 9. Machine 13.

In the first cleaning step, the object to be cleaned is subjected to the first cleaning in a total of two cleaning tanks 1 and 2 filled with a hydrocarbon (first cleaning agent) containing an additive. In the cleaning step (2), the additives and hydrocarbons adhering to the object to be cleaned are rinsed off in the cleaning tanks 3 and 4 filled with hydrocarbons, and in the third cleaning step, cyclic fluorocarbon or The immersion cleaning is performed in the cleaning tank 5 filled with the cyclic fluorocarbon containing an organic solvent (second cleaning agent), and the vapor cleaning is performed in the vapor zone 6.

A part of the second cleaning agent is transferred to the separation tank 9 by the circulation pump 12 and separated and purified (regenerated) by the cooling specific gravity separation method. The regenerated second cleaning agent is transferred to the steam generation tank 7, heated by the heating device 10, turned into steam, sent to the steam generation tank 6, and used again for steam cleaning. Further, the excess second cleaning agent is sent to the overflow tank 8 and is sent again to the steam generation tank 7 by the circulation pump 12.

When the high-purity second cleaning agent is not sufficiently regenerated by the separation tank 9, a high-purity second cleaning agent is installed by further installing a distillation column or the like (not shown). 2 cleaning agents can be obtained. Further, FIG. 1 illustrates the single-tank type washer 13, but the
Any number of tanks such as a tank type and a three-tank type may be used, and the number of washing tanks can be further increased in series or in parallel.

[0058]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present example and the comparative example were implemented using the cleaning apparatus shown in FIG.

(Example 1) Cleaning example of processing oil First, a commercially available hydrocarbon-based cleaning agent (trade name: NS-110, Nikko Petrochemical Co., Ltd.) was placed in cleaning tanks 1 and 2 of the cleaning apparatus shown in FIG. Cleaning tanks 3 and 4 containing 10% by weight of butyl carbitol and a commercially available hydrocarbon-based cleaning agent (trade name: NS-110, manufactured by Nikko Petrochemical Co., Ltd.) and cleaning tank 5 , 1,1,2,2,3,3,4-heptafluorocyclopentane, respectively.

On the other hand, ten mirror-finished parts (diameter 30 mm, thickness 3 mm) A were each fixed to a jig and immersed in a commercially available processing oil at room temperature. A mirror-finished part A was taken out of the processing oil, and was left to stand until oil drops of the processing oil did not drip.

One of the mirror-finished parts A (sample) to which the processing oil has adhered is immersed in the cleaning tank 1 and oscillated for 1.5 minutes, and then the mirror-finished part A is moved and immersed in the cleaning tank 2. And
1.5 while generating ultrasonic waves with the ultrasonic generator 11
Rocked for minutes. Further, the part A is transferred to the cleaning tank 3 and immersed and rocked for 1.5 minutes.
Rocked for minutes. Then, the part A was moved to the cleaning tank 5, immersed and rocked for 1.5 minutes, then moved into the steam zone 6, and subjected to steam cleaning for 1.5 minutes. By the same operation, the remaining nine mirror-finished parts A to which the processing oil adhered were sequentially washed.

(Embodiment 2) In Embodiment 1, the cleaning tank 5
In place of 1,1,2,2,3,3,4-heptafluorocyclopentane, 1,1,2,2,3,3,4-
The cleaning was performed in the same manner as in Example 1 except that a cleaning agent obtained by adding 2.5% by weight of methyl ethyl ketone (bp. 79.6 ° C.) to heptafluorocyclopentane was filled.

Comparative Examples 1 and 2 In Examples 1 and 2,
The cleaning was performed in the same manner as in Examples 1 and 2, except that the rinsing step with the cleaning tanks 3 and 4 was omitted.

(Evaluation of Cleaning Effect) The finished condition (the presence or absence of fogging and stains on the surface) of each sample (10 sheets) of Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated by visual observation.

As a result, in Example 1, although one of the washed samples showed slight fogging on its surface, the other nine samples had no fogging and stain on the surface.
Almost satisfactory cleaning effect was obtained. In Example 2, all of the ten samples after cleaning had no fogging or stain on the surface, and a satisfactory cleaning effect was obtained.

On the other hand, in Comparative Examples 1 and 2, ten samples were sequentially washed, and a satisfactory cleaning effect was obtained up to the first seven samples, but the remaining three samples were clouded on the surface. Alternatively, stains remained, and a decrease in the washing ability was observed during the repeated washing.

Then, the composition of the cleaning agent in the cleaning tank 5 after cleaning 10 samples was examined. As a result, in Examples 1 and 2, there was no change in the composition as compared to before cleaning, but in Comparative Examples 1 and 2, the cleaning agent (1, 1, 2, 2,3,3,4-heptafluorocyclopentane or 1,1,2,2,3,3,4-heptafluorocyclopentane to which 2.5% by weight of methyl ethyl ketone is added) and washing tanks 1 and 2 The butyl carbitol used in Example 1 was mixed. Comparative Example 2
In Comparative Example 1, the content of methyl ethyl ketone in the cleaning agent filled in the cleaning tank 5 was changed, and it was found that the composition of the cleaning agent in the cleaning tank 5 was significantly changed in each of Comparative Examples 1 and 2. .

For this reason, in Comparative Examples 1 and 2, the cleaning effect was reduced during the repetition of the cleaning because the cleaning tanks 1 and 2 did not.
When the sample (to-be-cleaned object) to which the cleaning agent is attached is replaced in the cleaning tank 5, the cleaning components (additive components) in the cleaning tanks 1 and 2 dissolve into the cleaning agent in the cleaning tank 5, and this is repeated. It is considered that the cause was that the composition of the composition of the cleaning agent in the cleaning tank 5 collected by the cooling specific gravity separation method changed during the period.

On the other hand, in the first and second embodiments, as described above, the cleaning tanks 3, 4
Since the rinsing was performed, the composition of the cleaning agent in the cleaning tank 5 did not change, and no reduction in the cleaning ability was observed even when the cleaning was performed continuously.

[0070]

As described above, the present invention relates to a method for cleaning an object to be cleaned, in which the object to be cleaned is cleaned with a hydrocarbon containing an additive and rinsed with a cyclic fluorocarbon solvent. The cleaning performance can be improved, the composition of each cleaning agent and the rinse cleaning agent does not change, the cleaning liquid can be easily managed, and the loss of the cleaning liquid can be reduced to reduce the running cost.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a cleaning apparatus that can carry out a cleaning method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cleaning tank 1, 2 ... Cleaning tank 2, 3 ... Cleaning tank 3, 4 ... Cleaning tank 4, 5 ... Cleaning tank 5, 6 ... Steam zone, 7 ... Steam generation tank, 8 ... Overflow tank, 9 ... Separation tank Reference numeral 10: heating device, 11: ultrasonic generator, 12: circulation pump, 13:
1 tank type washing machine

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C11D 7/32 C11D 7/32 7/50 7/50 F term (reference) 3B201 AA46 AB01 AB38 BB04 BB05 BB13 BB82 BB94 BB95 CC01 CC21 CD22 4H003 BA12 DA05 DA12 DA14 DA15 DA16 DC04 ED04 ED26 ED29 FA45

Claims (4)

[Claims] 1. A first cleaning step of cleaning an object to be cleaned with a first cleaning agent containing an additive and a hydrocarbon, and rinsing the object to be cleaned to which the cleaning agent has adhered using a hydrocarbon. A second cleaning step, and a third step of bringing the object to be cleaned rinsed with the hydrocarbon into contact with a cyclic fluorinated hydrocarbon or a second cleaning agent containing an organic solvent and a cyclic fluorinated hydrocarbon. A method for cleaning an object to be cleaned, comprising a cleaning step. 2. The method according to claim 1, wherein the additive is at least one selected from the group consisting of a polar solvent, a surfactant and a stabilizer. 3. The cyclic fluorinated hydrocarbon having a purity of 9%.
The method for cleaning an object to be cleaned according to claim 1, wherein trihydrofluorocarbon having 4 to 6 carbon atoms of 5% by weight or more is used. 4. The organic solvent having a boiling point of 25 to 300.
The method for cleaning an object to be cleaned according to any one of claims 1 to 3, wherein an organic solvent at ℃ is used.