JPH09125092A - Cleansing composition and cleansing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cleansing composition comprising the mixture of a specific ketone solvent with a hydrocarbon solvent such as an isoparaffinic solvent, high in safety for human bodies, capable of efficiently removing pitches or waxes from an article to be cleansed, and useful for the production of optical parts, etc. SOLUTION: This cleansing composition comprises the mixture of (A) a ketone solvent of the formula: R1 COR2 (R1 is a 1-4C alkyl; R2 is a 4-5C alkyl) such as 4-methyl-2-pentanone and (B) one or more kind of solvents selected from hydrocarbon solvents such as isoparaffinic solvents, normal paraffinic solvents and naphthenic solvents. The mixing ratio of the components A and B is 9/1 to 1/9, and the cleansing composition is preferably used together with ultrasonic waves on the low frequency side of <=30KHz.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a cleaning composition and a cleaning method used for cleaning pitches and waxes which are fixing adhesives during polishing and processing in the manufacturing process of optical components such as lenses and prisms. Regarding Further, the present invention relates to a cleaning composition and a cleaning method for cleaning an optical component to which an abrasive, a grinding oil, a protective film for protecting the polishing surface, or the like, or jigs and tools for processing the same, in addition to these pitches and waxes. .

[0002]

2. Description of the Related Art For cleaning as described above,
Chlorine-based organic solvents such as 1,1-trichloroethane, trichloroethylene, methylene chloride and perchloroethylene are used. Further, JP-A-3-36079 proposes a halogenated hydrocarbon or a mixed composition of a non-halogenated hydrocarbon, a fluorinated alcohol and a polar organic solvent as a cleaning composition for removing the fixing wax.
JP-A-6-93295 proposes a cleaning liquid containing a polar solvent, a surfactant, and water as a cleaning liquid that does not use a chlorine-based solvent having excellent rinsing properties.

Further, it is known that pitches are well dissolved in an aromatic hydrocarbon solvent. Therefore, the pitches are also washed with an aromatic hydrocarbon solvent such as toluene, xylene, or benzene. Further, JP-A-6-128592 proposes a cleaning liquid composed of a mixed composition of trimethylbenzene, methylethylbenzene, propylbenzene and N-methyl-2-pyrrolidone, which are derivatives of an aromatic hydrocarbon solvent.

[0004]

However, chlorine-based solvents, fluorine-based solvents, and cleaning liquids containing these have serious problems such as environmental pollution and safety for the human body.

Further, in the cleaning composition disclosed in JP-A-6-93295, the water content changes during use due to the mixing of the surfactant and water, and the liquid composition is not stable. Further, in a mixed composition of a ketone solvent and a polyhydric alcohol derivative, the dissolving power of pitch and wax is lowered by the polyhydric alcohol derivative. Moreover, the viscosity of the cleaning liquid increases, and even when cleaning is performed by using ultrasonic waves together, the effect of ultrasonic waves decreases, and there is a problem that the cleaning liquid is consumed by adhering it to an object to be cleaned and carrying it out. is there.

Further, when the cleaning liquid is regenerated by distillation, the liquid composition changes. For this reason, it cannot be recycled and becomes disposable, and the amount of cleaning liquid used becomes enormous, which greatly increases the running cost. In addition, the treatment of a large amount of industrial waste by discarding such a large amount of cleaning liquid becomes an environmental problem.

Next, since a cleaning liquid composed of a polar solvent and a surfactant generally has a high viscosity, similar to the above,
There are problems that the effect of cleaning by ultrasonic waves is reduced, a large amount of the cleaning agent attached to the object to be cleaned is taken out, and the cleaning liquid is heavily consumed.

On the other hand, the commonly used toluene,
Aromatic solvents such as xylene and benzene, and their derivatives such as trimethylbenzene, methylethylbenzene, propylbenzene and 1.1.1-trichloroethane, trichlorethylene, methylene chloride, perchlorethylene and other chlorine-based solvents are Highly toxic,
Subject to legal restrictions such as the Industrial Safety and Health Act and the organic solvent poisoning prevention rules. In addition, environmental pollution due to scattering due to evaporation and mixing into drainage has become a social problem. Therefore,
It is not preferable to use it as a cleaning liquid in consideration of the danger of handling this and its complexity.

The present invention has been made in consideration of these problems, and pitches, waxes, abrasives, grinding oils,
Provided is a cleaning composition which is excellent in dissolution and cleaning properties of a protective film and the like and is highly safe for human body and environment. Another object of the present invention is to provide a cleaning method using this cleaning liquid.

[0010]

The cleaning composition of the present invention comprises:
A mixed composition of a ketone solvent and an isoparaffinic solvent, a mixed composition of a ketone solvent and a normal paraffinic solvent, a mixed composition of a ketone solvent and a naphthene-based solvent, or a ketone solvent, a naphthene-based solvent and an isoparaffinic solvent. It is composed of a solvent or a mixed composition of normal paraffinic solvents. Here, the isoparaffin-based solvent, the normal paraffin-based solvent and the naphthene-based solvent are hydrocarbon-based solvents, while the ketone-based solvent has the following general formula. (In the formula, R ₁ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a propyl group, and R ₂ is an alkyl group having 4 to 5 carbon atoms.)

When the hydrocarbon solvent is at least one selected from an isoparaffin solvent, a normal paraffin solvent, and a naphthene solvent, the mixed composition of these cleaning compositions is: ketone solvent: hydrocarbon solvent = 9: 1
˜1: 9.

When the hydrocarbon solvent is a mixture of an isoparaffin solvent and a naphthene solvent, the weight mixing ratio of the mixed solvent is isoparaffin solvent: naphthene solvent = 9: 1 to 1: 9. Further, when the hydrocarbon-based solvent is a mixture of a normal paraffinic solvent and a naphthene-based solvent, the weight mixing ratio in this mixed solvent is a normal paraffin-based solvent and a naphthene-based solvent = 9: 1 to 1: 9.

The ketone-based solvent, isoparaffin-based solvent, normal paraffin-based solvent, and naphthene-based solvent used in the present invention do not contain halogen atoms such as chlorine and fluorine in the molecule, and therefore environmental destruction such as ozone layer destruction. Will not cause. In a ketone solvent,
In particular, 2,6-dimethyl-4-heptanone (diisobutyl ketone) is highly safe for the human body and does not fall under the organic solvent poisoning prevention regulations of the Industrial Safety and Health Law. Similarly, isoparaffin solvents, normal paraffin solvents, and naphthene solvents are known to have low toxicity to humans. In particular, isoparaffinic solvents and normal paraffinic solvents are extremely safe as they are used as cosmetics and fragrance solvents.

In terms of detergency, the ketone solvent has a good dissolving action on pitch, but the dissolving action on wax is slow depending on the type of wax, and when cleaning an object to be washed on which both the pitch and the wax adhere. However, it takes some time to completely remove the wax.

However, when mixed with an isoparaffinic solvent, a normal paraffinic solvent or a naphtheneic solvent,
These isoparaffin-based solvents, normal paraffin-based solvents, and naphthene-based solvents have a high action of swelling and dissolving in pitch and wax and a high penetrability, and have an action of separating dirt from the object to be washed. Due to the synergistic effect with the dissolving action of
Pitch and wax can be completely dissolved and removed in a short period of time with respect to dirt in a mixed system of pitch and wax, and good cleaning properties can be obtained. However, if the type of stain on the object to be cleaned is limited or if the degree of stain is mild, the ketone solvent can be used alone.

In the above-mentioned mixed composition, the composition ratio of the ketone-based solvent and the hydrocarbon-based solvent is such that when the object to be cleaned is pitch, the ketone-based solvent: hydrocarbon-based solvent = 3:
7 to 9: 1 is preferable, and a naphthene-based solvent is preferable as the hydrocarbon-based solvent in this case. The mixture composition ratio of the stains on the object to be cleaned to polar stains such as wax is preferably ketone solvent: hydrocarbon solvent = 5: 5 to 9: 1. As the hydrocarbon solvent, it is better to mix an isoparaffin solvent or a normal paraffin solvent than a naphthene solvent alone. Further, when the object to be cleaned is lightly contaminated with cutting oil or the like, it is possible to clean with a composition ratio of ketone solvent: hydrocarbon solvent = 4: 6 to 1: 9, which is a low-cost hydrocarbon. The cost of the cleaning liquid can be suppressed by increasing the amount of the system solvent. Further, although the ketone solvent has a strong odor, the odor can be suppressed by mixing it with a hydrocarbon solvent. Further, by increasing the amount of hydrocarbon solvent, the dissolving power of the cleaning liquid itself decreases, but since the viscosity of the cleaning liquid decreases, there is an effect of increasing the ultrasonic cleaning effect as a physical force, and cutting oil and the like. It is effective enough for light stains.

Further, the cleaning composition of the present invention is close to the flash point of a ketone solvent having a large flash point (eg, 2,6-dimethyl-4-heptanone: flash point 49 ° C.) and each of the ketone solvents ( ± 10 ° C is preferable) Isoparaffinic solvent, normal paraffinic solvent, and naphthene solvent are selected and mixed to make the flash point of the cleaning liquid 40 to 40
It can be maintained at 60 ° C. Therefore, even if the cleaning liquid is used at room temperature, it is possible to avoid the risk of ignition and ensure safety.

Further, when ultrasonic waves are used together in the washing machine, physical force is applied to the pitch and the wax, and good washing performance can be obtained in a short time. In particular, since the cleaning composition of the present invention can lower the viscosity of the cleaning liquid, the cavitation effect by ultrasonic waves is sufficiently exerted, and cleaning can be efficiently performed.

By the way, the composition of the cleaning liquid with the composition containing the surfactant is destroyed during regeneration by distillation. Therefore, the regenerated liquid cannot obtain a stable cleaning performance, and thus it is difficult to regenerate and use it by distillation. However, the boiling point of the cleaning liquid containing the composition of the present invention can be made extremely close to each other by combining a ketone solvent and an isoparaffin solvent, a normal paraffin solvent, or a naphthene solvent having a similar boiling point. As a specific example, 2,6-dimethyl-4-heptanone (boiling point 1
68 ° C.), the vapor pressure curve of each component is similar even if it is not an azeotropic composition if it is combined with an isoparaffinic solvent, a normal paraffinic solvent or a naphthene type solvent having a boiling range of 150 to 190 ° C. Therefore, it is possible to take an approximate azeotrope, and it is possible to recycle and use by regenerating by distillation without changing the composition ratio. Therefore, stable cleaning performance can be obtained and at the same time economical. Further, by performing this reuse, the amount of industrial waste can be extremely reduced.

In addition, by mixing an isoparaffinic solvent, a normal paraffinic solvent or a naphtheneic solvent having a low liquid unit price, there is an advantage that the cost of the cleaning liquid can be kept low.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The followings were used as stains used in the following embodiments. That is, the pitch is K1, K3, K8 as a straight asphalt type and KB4 (both are made by Kuju Electric Co., Ltd.) as a blown asphalt type, and the wax is a slot wax M,
Proof wax, yellow wax B, and sky wax M1 (both manufactured by Nikka Seiko Co., Ltd.) were selected.

As the cleaning composition, the ketone solvent used in each of the embodiments was used. As the hydrocarbon solvent mixed with the ketone solvent, Isosol 300 (manufactured by Nippon Petrochemical Co., Ltd.) was used as the isoparaffinic solvent. , NS Clean 100 (manufactured by Nikko Petrochemical Co., Ltd.) as a normal paraffin solvent, and Exol D as a naphthene solvent.
40 (manufactured by Exxon Chemical Co., Ltd.) was selected.

The isoparaffinic solvent is represented by the general formula C
_{Among the} chain saturated hydrocarbons represented by _n H _{2n + 2} (n is an integer), the boiling point is close to the boiling point (distillation range) of the ketone solvent to be mixed from the range of 150 to 190 ° C. I chose one. Similarly, as the naphthene-based solvent, among cyclic saturated hydrocarbons represented by the general formula C _n H _2n (n is an integer), a ketone-based solvent to be mixed is selected from the boiling point range of 150 to 190 ° C. Those close to the respective boiling points (distillation range) of the above were selected. Table 1 shows basic physical properties such as boiling points and flash points of ketone solvents, isoparaffin solvents, normal paraffin solvents, and naphthene solvents used in the following embodiments.

[0024]

[Table 1]

(Embodiment 1) In this embodiment, 4-methyl-2-pentanone and 2,6 are used as a ketone solvent.
-Dimethyl-4-heptanone was selected, and this and an isoparaffin solvent, a normal paraffin solvent, or a naphthene solvent were mixed at a weight ratio of 1: 1 to prepare a cleaning composition. In order to confirm the cleaning properties of these cleaning compositions for various pitches and waxes, the dissolved state of the pitches and waxes was confirmed. For comparison, 4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone, isoparaffin-based solvent, normal paraffin-based solvent, and naphthene-based solvent were used alone for cleaning.

During cleaning, the temperature of the cleaning liquid of each cleaning composition was room temperature (25 ° C.). No ultrasonic waves were used to confirm the solvency of the cleaning composition. The residual state of the pitch and wax after 30 minutes of immersion was confirmed and evaluated by the following rankings A to E. Pitch detergency is shown in Table 2 and wax detergency is shown in Table 3. A: No pitch or wax remained. Or the state where the pitch and wax are softened and flow, and are likely to be removed immediately with a light physical force B: The state where the pitch and wax are softened or peeled off C: The state where the pitch and wax are slightly softened or swollen D: Some Degree of surface change E: No change, no dissolution phenomenon

Further, the comprehensive evaluation is represented by ◯, Δ, and x. “◯” is an evaluation that corresponds to a heavy stain such as pitch or wax and has an excellent cleaning property. “Δ” is a level which is slightly inferior in cleanability, but is a level which is sufficiently effective when a small amount of pitch or wax is adhered or for light dirt such as cutting oil. In this case, even if the cleaning property is slightly inferior, it is economical and sometimes effective as a cleaning liquid. “X” is an evaluation that the cleaning power is poor and the target stain cannot be sufficiently removed.

[0028]

[Table 2]

[0029]

[Table 3]

As can be seen from Tables 2 and 3, cleaning in which 4-methyl-2-pentanone or 2,6-dimethyl-4-heptanone was mixed with an isoparaffin solvent, a normal paraffin solvent or a naphthene solvent. The composition was able to dissolve both the pitch and the wax in a shorter time than the case where the composition was washed by itself, and it was possible to obtain good detergency. Among them, the one showing the best cleaning properties for both pitch and wax is 4-methyl-
The cleaning composition was a mixture of 2-pentanone and a naphthenic solvent.

Further, when judging only by the dissolving power, a low molecular weight ketone solvent is preferable, but in view of safety to the human body, a high molecular weight ketone solvent such as 2,6-dimethyl-4-heptanone is used. It is better to use.

On the other hand, in order to improve the drying property, it is better to use a low molecular weight ketone solvent. As a specific example, a cleaning composition in which 4-methyl-2-pentanone (boiling point: 116 ° C.) and Isosol 200 (manufactured by Nippon Petrochemical Co., Ltd., boiling point: 95 to 135 ° C.) as a naphthenic solvent are mixed has good drying property. Is. In this way, various ketone solvents and isoparaffin solvents, normal paraffin solvents,
By utilizing the properties of the naphthene-based solvent such as the boiling point, the flash point, and the viscosity, it is possible to obtain a cleaning composition having the desired performance.

(Embodiment 2) From Embodiment 1, 2,6-dimethyl-4-heptanone is selected as a ketone solvent, and in order to confirm the detergency based on the mixing ratio of this and the naphthene solvent, a ketone is used. A cleaning composition was prepared in which the weight ratio of the system solvent and the naphthene system solvent was 9: 1, 7: 3, 5: 5, 3: 7, and 1: 9, respectively. In order to confirm the cleaning properties of the cleaning composition with respect to pitch and wax, a slide glass coated with 0.26 mm of pitch and wax was dipped in each cleaning composition for 30 minutes to confirm the dissolved state of the pitch and wax. The temperature of the cleaning liquid was normal temperature (25 ° C). No ultrasonic waves were used to confirm the solvency of the cleaning composition.

The cleaning properties with respect to pitch are shown in Table 4, and the cleaning properties with respect to wax are shown in Table 5. Detergency was evaluated by confirming the residual state of pitch and wax after 30 minutes of immersion and ranking by A to E. Also, a comprehensive evaluation is "○",
Indicated by “△” and “×”. The rank of these evaluations is the same as that of the first embodiment.

[0035]

[Table 4]

[0036]

[Table 5]

As can be seen from Tables 4 and 5, good detergency could be obtained in the mixed composition ratio range of 9: 1 to 1: 9.

Similarly, when an isoparaffinic solvent or a normal paraffinic solvent is used as the solvent mixed with the ketone solvent, the ketone composition is mixed with the ketone in the range of 9: 1 to 1: 9. When the mixed composition ratio of the system solvent and the normal paraffin solvent was in the range of 9: 1 to 1: 9, good detergency could be obtained.

(Embodiment 3) A ketone solvent, a naphthene solvent and a normal paraffin solvent or an isoparaffin solvent are mixed in a weight ratio of 2: 1: 1, respectively, and 3
A cleaning composition of mixed components was prepared. In order to confirm the cleaning properties of the cleaning composition with respect to pitch and wax, a slide glass coated with 0.26 mm of pitch and wax was immersed for 30 minutes to confirm the dissolved state of the pitch and wax. The temperature of the cleaning liquid was normal temperature (25 ° C). No ultrasonic waves were used to confirm the solvency of the cleaning composition.

Table 6 shows the cleaning properties with respect to pitch, and Table 7 shows the cleaning properties with respect to wax. Detergency was evaluated by confirming the residual state of pitch and wax after 30 minutes of immersion and ranking by A to E. Also, a comprehensive evaluation is "○",
Indicated by “△” and “×”. The rank of these evaluations is the same as that of the first embodiment.

[0041]

[Table 6]

[0042]

[Table 7]

As can be seen from Tables 6 and 7, a cleaning composition in which 4-methyl-2-pentanone or 2,6-dimethyl-4-heptanone and an isoparaffin solvent or a marmalparaffin solvent and a naphthene solvent are mixed. The product was able to obtain good detergency against a specific wax.

Similarly, as in the second embodiment, even if the weight mixing ratio of the solvent mixed with the ketone solvent is 9: 1 to 1: 9, good dissolution and cleaning properties are exhibited. The higher the ratio of the naphthene-based solvent to the pitch, the better the cleanability, and the higher the ratio of the wax to the isoparaffin-based solvent or the normal paraffin-based solvent. Therefore, by dissolving the normal paraffin or isoparaffin type solvent in a three-component system depending on the type of dirt of the specific cleaning product, the dissolution / cleanability can be improved.
When cleaning both pitch and wax at the same time, use a ketone solvent, naphthene solvent, normal paraffin solvent, or isoparaffin solvent in a ratio of 2: 1: 1.
It can handle stains with a wide range of weight mixing ratios.

(Embodiment 4) In this embodiment, 2,6-dimethyl-4-heptanone was used as a ketone solvent, and a three-component mixed composition was prepared by mixing this solvent with a naphthene solvent and isoparaffin. Naphthene solvent and isoparaffin solvent 9: 1, 7: 3, 5: 5, 3:
The weight ratio of this mixture to 2,6-dimethyl-4-heptanone was 1: 1.
It was mixed and adjusted.

In order to confirm the cleanability of the cleaning composition with respect to pitch and wax, the pitch and wax were adjusted to 0.
Apply 26 mm of slide glass to each cleaning composition.
It was immersed for a minute, and the dissolved state of pitch and wax was confirmed. The temperature of the cleaning liquid was normal temperature (25 ° C). No ultrasonic waves were used to confirm the solvency of the cleaning composition.

Detergency against pitch is shown in Table 8 and detergency against wax is shown in Table 9. Detergency was evaluated by confirming the residual state of pitch and wax after 30 minutes of immersion and ranking by A to E. Also, a comprehensive evaluation is "○",
Indicated by “△” and “×”. The rank of these evaluations is the same as that of the first embodiment.

[0048]

[Table 8]

[0049]

[Table 9]

As can be seen from these results, the mixture composition ratio of the solvent mixed with the ketone solvent is naphthene solvent:
In the range of isoparaffin solvent = 9: 1 to 1: 9, good detergency could be obtained.

(Embodiment 5) In this embodiment, 2,6-dimethyl-4-heptanone is used as a ketone solvent, and a three-component mixed composition is prepared by mixing this solvent with a naphthene solvent and normal paraffin. . Naphthene solvent and normal paraffin solvent 9: 1, 7: 3, 5:
The mixture was adjusted by mixing it in a weight ratio of 5, 3: 7, 1: 9, and this mixture was adjusted by mixing the mixture with 2,6-dimethyl-4-heptanone in a weight ratio of 1: 1.

In order to confirm the cleaning properties of the cleaning composition with respect to pitch and wax, the pitch and wax were mixed with 0.
Apply 26 mm of slide glass to each cleaning composition.
It was immersed for a minute, and the dissolved state of pitch and wax was confirmed. The temperature of the cleaning liquid was normal temperature (25 ° C). No ultrasonic waves were used to confirm the solvency of the cleaning composition.

Table 10 shows the cleaning properties with respect to pitch, and Table 11 shows the cleaning properties with respect to wax. Detergency was evaluated by confirming the residual state of pitch and wax after 30 minutes of immersion and ranking by A to E. In addition, the comprehensive evaluation is shown by “◯”, “Δ”, and “x”. The rank of these evaluations is the same as that of the first embodiment.

[0054]

[Table 10]

[0055]

[Table 11]

As can be seen from these results, the mixture composition ratio of the solvent mixed with the ketone solvent is naphthene solvent:
Normal paraffin solvent = in the range of 9: 1 to 1: 9,
Good detergency could be obtained.

(Embodiment 6) 2,6-dimethyl-4-
Table 12 shows the results of cleaning using a cleaning composition in which heptanone and a naphthene-based solvent were mixed at a weight ratio of 1: 1, with or without ultrasonic cleaning, and with ultrasonic frequency of low frequency or high frequency. Show. The low frequency side is 28 KHz,
The frequency on the high frequency side was 40 KHz. These frequencies are commonly used for cleaning.

As a cleaning sample, an optical glass lens (glass material FSL5, manufactured by Ohara Optical Glass Manufacturing Co., Ltd.) having a pitch K1, an abrasive, and a protective film (hard coat # 3, manufactured by Kuju Denki Co., Ltd.) attached thereto. ) Was used. 28KH for cleaning
z, 600 W, or 40 KHz, 600 W ultrasonic oscillator is installed in the cleaning machine, the above-mentioned cleaning composition is filled, and the above-mentioned cleaning object is immersed in this cleaning composition for cleaning, and the pitch is completely The time required for cleaning was measured. The temperature of the cleaning liquid was normal temperature (25 ° C).

[0059]

[Table 12]

As can be seen from Table 12, when ultrasonic waves are used in combination, the pitch and wax swollen and softened by the cleaning solution are easily peeled off due to the cavitation effect of ultrasonic waves.
It is decomposed and can be thoroughly cleaned efficiently in a short time. In addition, in this cleaning composition, 3
The use of low-frequency ultrasonic waves of 0 KHz or less has a further cleaning effect and enables efficient cleaning.

(Embodiment 7) From the cleaning composition of Embodiment 1, 2,6-dimethyl-4-heptanone and a naphthenic solvent (Exol D40) are selected, and the mixing ratio is 9: weight. The composition ratio after distillation regeneration by a vacuum distillation apparatus was confirmed by changing the ratio to 1 to 1: 9. Table 13 shows the composition ratio after distillation.
Shown in As distillation conditions, distillation was carried out at a distillation temperature of 103 ° C. (vapor pressure 4 kg / cm ² ) and a degree of reduced pressure of 730 mmHg. As the vacuum distillation device, DC-31 (manufactured by Olympus Optical Co., Ltd.) was used.

[0062]

[Table 13]

As can be seen from Table 13, since the boiling points of 2,6-dimethyl-4-heptanone and the naphthene-based solvent are close to each other, an approximate azeotrope is formed, and the composition ratio after distillation does not sufficiently affect detergency. Therefore, it can be reused by recycling.

[0064]

INDUSTRIAL APPLICABILITY The cleaning composition of the present invention is capable of efficiently cleaning and removing pitches and waxes used for processing lenses and prisms of optical parts from an object to be cleaned, as well as an abrasive and a grinding oil. It is also possible to clean the protective film and the like. Moreover, the cleaning composition of the present invention is highly safe for humans and inexpensive, without damaging the environment.

In the cleaning method of the present invention, since the cleaning composition described above and ultrasonic waves are used in combination, pitches and waxes can be removed reliably and rapidly.

Claims (3)

[Claims] 1. A ketone solvent having a ketone bond represented by the following general formula and at least one solvent selected from isoparaffin solvents, normal paraffin solvents or hydrocarbon solvents such as naphthene solvents are mixed. A cleaning composition comprising: (In the formula, R ₁ is an alkyl group having 1 to 4 carbon atoms, and R ₂ is an alkyl group having 4 to 5 carbon atoms.) 2. The mixture composition ratio of the ketone solvent and the hydrocarbon solvent is as follows: ketone solvent: hydrocarbon solvent = 9: 1
The cleaning composition according to claim 1, wherein the composition ratio is 1: 9, and the hydrocarbon solvent is an isoparaffin solvent, a normal paraffin solvent, or a naphthene solvent, either alone or in a mixture. 3. A cleaning method, wherein the cleaning composition according to claim 1 or 2 is used in combination with ultrasonic waves on the low frequency side of 30 KHz or less.