JP4710265B2 - Cleaning composition and cleaning system using the same - Google Patents

Description

  The present invention removes various contaminants such as adhering oily and water-soluble processing oil and water from processed parts and products in various industrial fields such as automobiles, machines, precision equipment, electricity and electronics (hereinafter referred to as parts). More specifically, it is a combination of oily processing oil, water-based processing oil, water, and other complex stains, regardless of the shape of the parts, etc., at low temperatures below the flash point under atmospheric pressure or under reduced pressure. It can be washed at high temperature, no rinse agent such as water is needed after washing, it can be dried as it is, low toxicity, safe and stable cleaning agent that can be used repeatedly while regenerating, and cleaning using it About the system.

  Parts processed in various industrial fields such as automobiles, machinery, precision equipment, electricity, electronics, etc. are processed by adding a surfactant to oil-based processing oils, mineral oils, etc. mainly composed of mineral oils. A water-based processing oil emulsified in water, water, etc. are used, and it is necessary to wash in order to remove them. Usually, processing of parts or the like is composed of a plurality of processes, and the processing oil used for each process is often different. Accordingly, various processed oils and the like are attached to the processed parts and the like in combination. Conventionally, these stains are removed by washing with a chlorinated solvent, washing with isopropanol (IPA), alkali, acid, Washing with an aqueous detergent containing a surfactant and water has been performed. However, the use of chlorinated solvents is difficult due to environmental protection and toxicity problems, and IPA has a high flash point because of its low flash point, and its cleanability is insufficient. Since water-based cleaning agents contain components that do not volatilize, it is necessary to rinse with pure water after cleaning, so that stains and rust are likely to occur after cleaning, resulting in a large cleaning facility, pure water production facility and wastewater treatment There are many problems such as the need for incidental equipment such as equipment.

  For these problems, a semi-aqueous cleaning agent (for example, see Patent Documents 1 and 2), a hydrocarbon-based cleaning agent, an alcohol-based cleaning agent (for example, see Patent Document 3) or a mixture of a solvent such as glycol ether and water. A cleaning agent that can be regenerated by distillation (see, for example, Patent Document 4) has been proposed.

JP-A-11-199896 (Claim 1) JP 2004-107561 A (Claim 1) JP-A-9-25496 (Claims 1, 2 and 3) JP-A-9-49000 (Claims 1, 5, 6)

  However, such cleaning agents have the following problems. In the case of the semi-aqueous cleaning agents of Patent Documents 1 and 2, the dirt is not dissolved, but is removed (dropped, floated, emulsified) from the object to be cleaned. Accordingly, in a case having a bag hole or a fine object to be cleaned, the dirt cannot be sufficiently removed and remains on the object to be cleaned, and the cleaning property becomes insufficient. In addition, when a surfactant is added to the semi-aqueous cleaning agent in order to enhance the cleaning power, it is necessary to rinse with pure water after cleaning, and management such as a pure water production facility and a waste water treatment facility is troublesome. In the case of a hydrocarbon-based cleaning agent, oily soil such as oily processing oil can be dissolved and removed, and the cleaning property is high, but aqueous cleaning soil such as aqueous processing oil and water cannot be dissolved, so that the cleaning property is poor. When removing aqueous dirt with a hydrocarbon-based cleaning agent, a hydrocarbon-based cleaning agent containing a draining agent is used. In this case, since the aqueous dirt is peeled off and removed, the cleaning property is insufficient depending on the shape of the object to be cleaned as described above, and it is necessary to rinse after cleaning. In the alcohol-based cleaning agent of Patent Document 3, any dirt is not sufficiently cleanable, and there is a problem with reuse of the cleaning agent. Patent Document 4 proposes a cleaning agent containing an alcoholic organic solvent and cresol, xylenol, and the like, and cresol and the like are distilled together with the alcoholic organic solvent when the cleaning agent is distilled. . However, these compositions have a problem that they cannot be used repeatedly because of poor thermal stability and deterioration of the cleaning agent due to cleaning at high temperature under reduced pressure or distillation regeneration.

  In the present invention, the object to be cleaned to which oily dirt, aqueous dirt, and composite dirt thereof are attached is washed at a low temperature below the flash point under atmospheric pressure regardless of its shape (for example, 0 to 40 ° C. ) And high-temperature washing under reduced pressure (for example, 50 to 100 ° C.), low-toxicity that can be reused by separating dirt from the cleaning agent without being rinsed such as water and allowing it to dry as it is after cleaning. Therefore, it is to provide a safe and highly stable cleaning agent.

  In view of such circumstances, the present inventors have made various studies to solve the above-mentioned problems, and as a result, have found a target cleaning agent and have completed the present invention.

  That is, the detergent composition comprises 100 parts by weight of propylene glycol mono n-propyl ether and 0.001 to 0.1 parts by weight of 2,6-di-tert-butyl-p-cresol.

  Hereinafter, the present invention will be described in more detail.

  Propylene glycol mono-n-propyl ether used in the cleaning agent of the present invention has low toxicity and has a flash point of 40 ° C. or higher, so that it can be handled safely, and is compatible with water at an arbitrary ratio. Because it dissolves and has oil solubility, and can dissolve oily soil, water-based soil, and their combined soil at the same time, regardless of the shape of the object to be cleaned, cleaning at a low temperature below the flash point under atmospheric pressure In addition, cleaning at a high temperature under reduced pressure can be performed satisfactorily. Furthermore, since it has a boiling point of about 150 ° C. and does not contain components that do not volatilize such as surfactants and alkali agents, the object to be cleaned can be dried as it is by hot air drying, vacuum drying or the like after washing. Furthermore, since the boiling point is far away from the boiling point of water and oil, which are the components of dirt, it is easy to separate from dirt components by distillation, etc., and is stable under the distillation conditions, It can be used repeatedly.

  In addition to propylene glycol mono n-propyl ether, tetrahydrofurfuryl alcohol as an alcohol, ethyl lactate as an ester, polyvalent Examples of alcohols include diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, 3-methoxy-1-butanol, and 3-methyl-3-methoxy-1-butanol. However, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol diethyl ether have low viscosity and are more water-soluble. Sex is good, solubility of the surfactant or the like contained in the aqueous stain is insufficient. Moreover, since ethyl lactate, dipropylene glycol monomethyl ether, tetrahydrofurfuryl alcohol, 3-methoxy-1-butanol, and 3-methyl-3-methoxy-1-butanol are soluble in soil, but have a low dissolution rate. There is a problem that the detergency is poor, and since propylene glycol monoethyl ether has a boiling point close to that of water, there is a problem that it is difficult to regenerate and use because of poor separation from water.

  One or more solvents selected from diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, 3-methoxy-1-butanol, and 3-methyl-3-methoxy-1-butanol are added to propylene glycol mono n-propyl ether. When 30 parts by weight or less is blended, the detergency can be further improved without deteriorating the function of the detergent. For example, by adding diethylene glycol dimethyl ether and diethylene glycol methyl ethyl ether, the dissolution rate of water increases, and by adding 3-methoxy-1-butanol and 3-methyl-3-methoxy-1-butanol, it is included in aqueous stains This improves the solubility of oils and surfactants, and improves the detergency. These components can be selected according to the type and state of the dirt. Even if these components are contained in an amount exceeding 30 parts by weight, the cleaning properties are not improved, and conversely, the cleaning properties and drying properties of the cleaning agent are deteriorated, which is not preferable.

  It should be noted that a solvent that is incompatible with water at an arbitrary ratio peels off aqueous stains, so that even if it has a good cleaning property (peeling property), the cleaning property is insufficient depending on the object to be cleaned.

  The 2,6-di-tert-butyl-p-cresol contained in the cleaning agent of the present invention is blended in an amount of 0.001 to 0.1 parts by weight with respect to 100 parts by weight of propylene glycol mono n-propyl ether. As a result, the stability can be enhanced without deteriorating the function of the cleaning agent, and the heated cleaning and cleaning agent can be regenerated and used repeatedly. The regeneration of the cleaning agent can be performed by distillation, which is advantageous in terms of equipment costs. When the blending amount of 2,6-di-tert-butyl-p-cresol is less than 0.001 part by weight with respect to 100 parts by weight of propylene glycol mono-n-propyl ether, oxidative degradation of the cleaning agent during distillation or the like This is likely to occur, and since the acid content is generated, the metal parts and the like are affected by discoloration and the like, so that the cleaning agent cannot be used repeatedly. Moreover, when it exceeds 0.1 weight part, when drying a to-be-washed | cleaned material, it will remain in a to-be-washed | cleaned material as a non volatile matter, and is not preferable.

  Even if a phenol-based, amine-based, phosphorus-based or sulfur-based antioxidant is used in place of 2,6-di-tert-butyl-p-cresol, the effect of the present invention cannot be obtained. For example, when phenolic antioxidants such as pyrocatechin, 4-methoxyphenol, and n-propyl gallate are used, it is not possible to sufficiently prevent acid generation of the cleaning agent by heating. In addition, when hydroquinone is used, generation of acid content of the cleaning agent by heating can be suppressed, but the coloring of the cleaning agent is remarkable, which is not preferable. In addition, amine-based, phosphorus-based, and sulfur-based antioxidants have a remarkably high boiling point and do not volatilize. Therefore, when the object to be cleaned is dried, it remains as a non-volatile component in the object to be cleaned, or the detergent is distilled. When reproducing, there is a problem that almost the whole amount is lost.

  The cleaning method and the drying method using the cleaning agent of the present invention are not particularly limited. For example, the cleaning method is immersion cleaning, rocking cleaning, rotational cleaning, ultrasonic cleaning, shower cleaning under atmospheric pressure or reduced pressure. And vacuum vapor cleaning can be used. Moreover, about a drying system, warm air drying, suction drying, rotary drying, vacuum drying, substitution drying with a nonflammable low boiling point solvent, etc. can be implemented. These cleaning methods and drying methods can be used alone or in combination of several types in consideration of the required cleanliness and required time. If these are provided with a distillation function and a dehydration function that reduce the dirt and moisture concentration of the cleaning agent that increases with cleaning, the performance of the cleaning agent of the present invention can be more fully exhibited. The vacuum cleaning and drying system with distillation and dehydration functions can regenerate the cleaning agent more efficiently, and it can be washed with a washing machine with distillation and dehydration functions and replaced with nonflammable low-boiling solvent. In the cleaning system, since cleaning and drying can be performed in a short time, any of them can be preferably used.

  Repeated cleaning of the object to be cleaned, which is a combination of oily and aqueous stains, will gradually increase the moisture concentration of the cleaning agent and gradually deteriorate the solubility of the oily soil. It is necessary to keep the water concentration to 25% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less. By providing the washing system with a dehydration function, the moisture concentration of the cleaning agent can be kept within a certain range. And good cleanability can be maintained.

  As a method of dehydrating the cleaning agent of the present invention, a method of flushing moisture by exposing the heated cleaning agent to a reduced-pressure atmosphere, a method of contacting the cleaning agent with air or nitrogen to dissipate moisture, and multi-stage distillation of the cleaning agent Method, Method of contacting cleaning agent with zeolite or silica gel to adsorb moisture, Mixing hydrophobic solvent such as hydrocarbon and cleaning agent to separate two layers, separating moisture, Separating by pervaporation membrane However, in view of equipment cost, operability, etc., a method of flushing moisture, a method of releasing moisture, and a method of adsorbing moisture on zeolite or the like are preferable.

  The cleaning agent of the present invention consists of a solvent system with low toxicity, safety and stability, and is suitable for an object to be cleaned to which oily soil, aqueous soil and composite soil thereof are attached, regardless of its shape. Since washing at low temperature below the flash point under atmospheric pressure and washing at high temperature under reduced pressure can be performed well, it can be dried as it is after washing without rinsing agent such as water, and dirt from the cleaning agent It can be reused repeatedly while separating.

Examples 1-7, Comparative Examples 1-15
A cleaning test was conducted on the following A and B stains. After the dirt A or B is attached to the bolt, and the weight is measured, the dirt is gently immersed in 100 ml of a cleaning agent maintained at a temperature of 40 ° C. The amount was measured. The removal rate was calculated from the amount of dirt before washing and the amount of dirt after the test, and the washability was evaluated according to the following evaluation criteria. The compositions of Examples 6 and 7 were obtained by distilling and recovering the compositions described in Examples 1 and 4 under the following conditions using an evaporator.

Removal rate = (1− (dirt amount after washing / dirt amount before washing)) × 100 (%)
Dirt A: Brassocut 2000U (Cutting oil manufactured by Brother Swiss Lube)
B: Emulsion of Buracut 2000U
(Brazocut 2000U / water = 10/90% by weight)
Cleaning time Dirt A: 2 minutes, Dirt B: 1 minute Evaluation of detergency ◎: Dirt removal rate of 95% or more
○: Dirt removal rate of 85% to less than 95%
Δ: Dirt removal rate of 75% to less than 85%
X: Dirt removal rate of less than 75% Distillation recovery conditions Pressure: 50 mmHg, Recovery rate: 95% by weight
The test results are shown in Table 1. The cleaning composition of the present invention showed excellent detergency against soil A (soil mainly composed of mineral oil and surfactant) and soil B (stain mainly composed of mineral oil, surfactant and water). .

実施例８〜１６、比較例１６〜１９
表２に示した組成物３０ｍｌを１００ｍｌ試験管に入れ、試験管上部に還流冷却器を取り付けて、１００℃のオイルバスに浸漬して加熱した。２４時間後、組成物の酸分を適定法により測定し、下記評価基準で安定性を評価した。実施例１５と１６の組成物は、実施例９及び１３に記載の組成物をエバポレーターを使用して下記条件で蒸留回収したものである。

Examples 8-16, Comparative Examples 16-19
30 ml of the composition shown in Table 2 was put into a 100 ml test tube, a reflux condenser was attached to the upper part of the test tube, and immersed in a 100 ° C. oil bath and heated. After 24 hours, the acid content of the composition was measured by an appropriate method, and the stability was evaluated according to the following evaluation criteria. The compositions of Examples 15 and 16 were obtained by distilling and recovering the compositions described in Examples 9 and 13 using an evaporator under the following conditions.

Evaluation of stability A: Less than 10 ppm of product acid content (as acetic acid)
○: Product acid content (as acetic acid) 10 ppm or more and less than 50 ppm
Δ: Product acid content (as acetic acid) 50 ppm or more and less than 100 ppm
×: Product acid content (as acetic acid) 100 ppm or more Distillation recovery conditions Pressure: 50 mmHg, Recovery: 95% by weight
These test results are shown in Table 2. The cleaning agent of the present invention did not increase the acid content as compared with the comparative example, and showed excellent stability.

実施例１７
図１に示す真空洗浄システムで、本発明の洗浄剤（プロピレングリコールモノｎ−プロピルエーテル：２，６−ジ−ｔｅｒｔ−ブチル−ｐ−クレゾール＝１００重量部：０．０５重量部）を使用して汚れＢが付着したボルトを繰り返し洗浄した。

Example 17
In the vacuum cleaning system shown in FIG. 1, the cleaning agent of the present invention (propylene glycol mono-n-propyl ether: 2,6-di-tert-butyl-p-cresol = 100 parts by weight: 0.05 parts by weight) is used. The bolts with dirt B adhered thereto were washed repeatedly.

  The cleaning system in FIG. 1 includes a cleaning agent tank 1 containing a cleaning agent 2, a cleaning / drying tank 4 for cleaning and drying an object to be cleaned, and a pump for moving the cleaning agent 2 from the cleaning / drying tank 4 to the cleaning agent tank 1. 6, a cleaning agent tank 1 and a cleaning / drying tank 4, a vacuum pump 7 for reducing the pressure, a vacuum pump 7, a recovery tank 8 containing the cleaning agent 2, a recovery tank 8 and a vacuum pump 11. The dehydrating tank 10 is connected to the dehydrating tank 10 and the vacuum distiller 12 is connected to the dehydrating tank 10 to distill the dehydrated cleaning agent.

  The cleaning agent 2 of the present invention housed in the cleaning agent tank 1 is heated to 70 ° C. by the heater 3, and at the same time, the cleaning agent tank 1 is decompressed to 50 mmHg by the vacuum pump 7. In addition, the cleaning agent in the cleaning agent tank 1 is continuously sent to the vacuum distillation machine 12 through a pipe to remove high-boiling soil components and then returned to the cleaning agent tank 1 through the pipe. The object to be cleaned (not shown) is carried in by opening the lid of the cleaning / drying tank 4 brought to atmospheric pressure, the lid of the cleaning / drying tank 4 is closed, the pressure is reduced to 50 mmHg by the vacuum pump 7, and then the pipe is connected from the cleaning agent tank 1. Then, the cleaning agent 2 is received, the object to be cleaned is immersed, and ultrasonic cleaning is performed by the ultrasonic oscillator 5 attached to the cleaning / drying tank 4. After ultrasonic cleaning for 1 minute, the pressure of the cleaning / drying tank 4 is returned to 200 mmHg, and the cleaning agent is moved to the cleaning agent tank 1 by the pump 6. Thereafter, the washing and drying tank 4 is further depressurized to 1 mmHg or less by the vacuum pump 7 and dried. After drying, air is introduced into the washing / drying tank 4 to return to atmospheric pressure, the lid of the washing / drying tank 4 is opened, and the object to be washed is taken out.

  Moisture and cleaning agent vapor that evaporates as the cleaning tank 1 and the cleaning / drying tank 4 are depressurized are blown into the recovery tank 8 through the vacuum pump 7 and cooled to 25 ° C. by a cooler 9 attached to the recovery tank 8. It is condensed and recovered by the cleaning agent 2. The cleaning agent 2 in the recovery tank 8 is sent to the dehydration tank 10 as the liquid level rises, and is reduced to 100 mmHg by the vacuum pump 11 while being heated to 50 ° C. by the heater 3 in the dehydration tank 10 to evaporate the water. The cleaning agent in the dehydrating tank 10 is sent to the vacuum distiller 12 as the liquid level rises, and the high-boiling soil components are separated and returned to the cleaning agent tank 1 for reuse.

  As a result of repeatedly washing the bolts with dirt B in the vacuum cleaning system described above, the water concentration of the cleaning agent 2 in the cleaning tank 1 is 1 to 2% by weight, and the water concentration of the cleaning agent 2 in the recovery tank 8 is 20 to 25%. The water concentration of the cleaning agent 2 in the dehydration tank 10 was 15 to 20% by weight and was in an almost equilibrium state, and good cleaning could be repeatedly performed while regenerating and reusing the cleaning agent.

Example 18
In the vacuum cleaning system shown in FIG. 2, the cleaning agent of the present invention (propylene glycol mono n-propyl ether: 2,6-di-tert-butyl-p-cresol = 100 parts by weight: 0.05 parts by weight) is used. The bolts with dirt B adhered thereto were washed repeatedly.

  The cleaning system shown in FIG. 2 has a space at the top, a cleaning agent 2 that contains a cleaning agent 2 at the bottom, a heater 3 that heats the cleaning agent 2, and can be partitioned by a gate valve 19 provided in the middle. A vacuum pump 7 for depressurizing the cleaning / drying tank 4, a recovery tank 8 connected to the vacuum pump 7, containing a cleaning agent 2, a dehydration tank 10 connected to the recovery tank 8 and the vacuum pump 11, and a dehydration tank 10 The vacuum distillation machine 12 which connects and distills the cleaning agent after dehydration is comprised.

  The cleaning agent 2 stored in the cleaning / drying tank 4 is heated to 70 ° C. by the heater 3 and simultaneously reduced in pressure to 100 mmHg by the vacuum pump 7. In addition, the cleaning agent 2 in the cleaning / drying tank 4 is continuously sent to the vacuum distiller 12 through a pipe, and after removing high-boiling soil components, it is returned to the cleaning / drying tank 4 through the pipe. The object to be cleaned (not shown) is loaded by opening the lid of the cleaning / drying tank 4 with the gate valve 19 closed and the upper space at atmospheric pressure, and the lid of the cleaning / drying tank 4 is closed and the pressure is reduced to 100 mmHg by the vacuum pump 7. After that, the gate valve 19 is opened, the object to be cleaned is moved to the lower part and immersed in the cleaning agent 2 for cleaning. An ultrasonic oscillator 5 is attached to the cleaning / drying tank 4 to perform ultrasonic cleaning. After the object to be cleaned is ultrasonically cleaned for 1 minute, the object to be cleaned is moved to the upper space, the gate valve 19 is closed, and the upper space of the cleaning / drying tank 4 is further reduced to 1 mmHg or less by the vacuum pump 7 and dried. After drying, air is introduced into the upper space of the cleaning / drying tank 4 to return to atmospheric pressure, the lid of the upper space of the cleaning / drying tank 4 is opened, and the object to be cleaned is taken out.

  Moisture and cleaning agent vapor evaporated in the cleaning / drying tank 4 at the time of cleaning and drying are blown into the recovery tank 8 through the vacuum pump 7 and condensed by the cleaning agent 2 cooled to 25 ° C. by the cooler 9 in the recovery tank 8. And collect. The cleaning agent 2 in the recovery tank 8 is sent to the dehydration tank 10 as the liquid level rises, heated to 45 ° C. by the heater 3 in the dehydration tank 10, and depressurized to 50 mmHg by the vacuum pump 11 to evaporate moisture. The cleaning agent 2 in the dehydrating tank 10 is sent to the vacuum distiller 12 as the liquid level rises, and the high-boiling soil components are separated and returned to the cleaning / drying tank 4 for reuse.

  As a result of repeatedly washing the bolt with the dirt B attached in the vacuum cleaning system, the water concentration of the cleaning agent 2 in the cleaning / drying tank 4 is 3 to 4% by weight, and the water concentration of the cleaning agent 2 in the recovery tank 8 is 15 to The water concentration of the cleaning agent 2 in the dehydrating tank 10 was 20% by weight and was in an almost equilibrium state at 10 to 15% by weight, and good cleaning could be repeatedly performed while regenerating and reusing the cleaning agent.

Example 19
In the cleaning system shown in FIG. 3, the bolt with the dirt B attached thereto was replaced with the cleaning agent of the present invention (propylene glycol mono n-propyl ether: 2,6-di-tert-butyl-p-cresol = 100 parts by weight: 0.05). Parts by weight), and substitution drying was repeated using a fluorine-based inert solvent.

  The cleaning system shown in FIG. 3 includes a cleaning unit and a vapor drying unit. The cleaning unit includes a two-tank cleaning machine 13 containing the cleaning agent 2, a dehydration tank 10 connected to the two-tank cleaning machine 13 and the vacuum pump 11. And a vacuum distiller 12 connected to the dehydration tank 10 for distilling the dehydrated cleaning agent. The vapor drying section contains a fluorine-based inert solvent 15 at the bottom and a cooler 9 at the top. A vapor drying tank 14, a water separator 16 for separating the fluorinated inert solvent and water condensed by the cooler 9, a vapor generator 17 for generating fluorinated inert solvent vapor, and a fluorine generator for the vapor generator. It comprises a distiller 18 for distilling the active solvent.

  The cleaning agent 2 stored in the two-tank cleaning tank 13 is continuously sent to the vacuum distiller 12 through the dehydrator 10 through the piping, and after removing moisture and high-boiling soil components, returns to the two-tank cleaning tank 13. ing. In the dehydration tank 10, the cleaning agent 2 is maintained at 40 ° C. and 50 mmHg by the heater 3 and the vacuum pump 11. The fluorine-based inert solvent 15 in the vapor drying tank 14 is sent to the vapor generator 17 and is always heated to the boiling point by the heater 3. The generated vapor is sent to the middle stage of the vapor drying tank 14. The fluorine-based inert solvent in the vapor generator 17 is extracted to the distillation machine 18 when it rises by 5 ° C. compared to the boiling point before the cleaning is started, and the fluorine-based inert solvent recovered by the distillation machine 18 is removed from the vapor generator 17. Return to.

  The object to be cleaned (not shown) is immersed in the first tank of the two tank type cleaning tank 13 for cleaning. An ultrasonic oscillator 5 is attached to the first tank of the two tank cleaning tank 13 and performs ultrasonic cleaning. After the object to be cleaned is ultrasonically cleaned for 1 minute, the object to be cleaned is moved to the second tank of the two tank type cleaning tank 13 and immersed and cleaned for 1 minute. Next, the object to be cleaned is moved to the lower part of the vapor drying tank 14 and immersed in the fluorine-based inert solvent 15, and is replaced with the fluorine-based inert solvent by applying ultrasonic waves for 1 minute by the ultrasonic oscillator 5. Thereafter, the object to be cleaned is moved onto the surface of the fluorinated inert solvent 15 and heated for 1 minute by the vapor introduced from the vapor generator 17, and then the object to be cleaned is pulled up to the position of the cooler 9 for 1 minute. Hold and dry.

  As a result of repeated washing and barper drying of the bolts with the dirt B attached, the above cleaning system was able to perform good cleaning while regenerating and reusing the cleaning agent.

Configuration diagram of cleaning system of Example 17 Configuration diagram of cleaning system of Example 18 Configuration diagram of cleaning system of Example 19

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cleaning agent tank 2 Cleaning agent 3 Heater 4 Washing drying tank 5 Ultrasonic oscillator 6 Pump 7 Vacuum pump 8 Collection tank 9 Cooling device 10 Dehydration tank 11 Vacuum pump 12 Vacuum distillation machine 13 Two tank type washing machine 14 Vapor drying tank 15 Fluorine-based inert solvent 16 Water separator 17 Vapor generator 18 Distiller 19 Gate valve

Claims (3)

A cleaning composition comprising 100 parts by weight of propylene glycol mono n-propyl ether and 0.001 to 0.1 parts by weight of 2,6-di-tert-butyl-p-cresol. 100 parts by weight of propylene glycol mono n-propyl ether, 0.001 to 0.1 parts by weight of 2,6-di-tert-butyl-p-cresol, and diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, 3-methoxy-1-butanol A cleaning composition comprising at least 30 parts by weight of at least one solvent selected from 3-methyl-3-methoxy-1-butanol. Washing and drying steps of the object to be cleaned using the cleaning agent composition of claim 1 or 2, cleaning method characterized in that it is composed of the recovery process and dewatering process of the washing agent.

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