JPH09183999A - Cleaning composition and cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cleanly remove pitch and wax stuck in the process of manufacturing optical parts. SOLUTION: Cleaning is made with a cleaning composition consisting of a mixture of a benzyl acetate as represented by the formula (wherein R is a methyl group or an ethyl group.) and a naphthene solvent. The benzyl acetate readily dissolves wax and the naphthene solvent swells and releases pitch and wax and the synergistic cleaning developed by mixing both components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning composition for removing pitches and waxes, which are adhesives for fixing during polishing and processing, which are mainly used in the manufacturing process of lenses and prisms of optical parts. And a cleaning method. Further, the present invention relates to a cleaning composition and a cleaning method for cleaning not only pitches and waxes, but also optical components to which an abrasive, cutting oil, a protective film for protecting a polishing surface or the like is attached or jigs and tools for processing the same. .

[0002]

2. Description of the Related Art To clean the above-mentioned parts and members,
Chlorine-based solvents such as 1,1-trichloroethane, trichloroethylene, methylene chloride and perchloroethylene are used. On the other hand, JP-A-3-36079 discloses a halogenated hydrocarbon or a non-halogenated hydrocarbon, a fluorinated alcohol and a polar organic solvent as a cleaning composition for removing a wax used for fixing an optical component. Mixed compositions have been proposed. Furthermore, JP-A-6-9329
Japanese Patent Laid-Open Publication No. 5 proposes a cleaning liquid containing a polar solvent, a surfactant and water as a cleaning liquid excellent in rinsing property without using a chlorine-based solvent.

It is known that pitches are well dissolved in an aromatic hydrocarbon solvent. Therefore, pitches have been removed using an aromatic hydrocarbon solvent such as toluene, xylene, or benzene. Also,
JP-A-6-279786 proposes a detergent containing hydrocarbons and esters as a detergent for waxes. Furthermore, JP-A-6-3409898 proposes a cleaning composition using a carbonic acid ester.

[0004]

A chlorine-based solvent, a fluorine-based solvent, or a cleaning liquid containing these has a serious problem in terms of environmental pollution and safety for the human body.

The cleaning composition of JP-A-6-93295 changes the amount of water during use due to the mixing of the surfactant and water, and also changes the composition when regenerated by distillation or the like. For this reason, this cleaning composition cannot be reused and becomes disposable, resulting in an enormous amount of use and a significant increase in running cost. In addition, when disposing as industrial waste, the amount increases, which causes a problem in processing. Furthermore, since a cleaning composition composed of a polar solvent and a surfactant generally has a high viscosity, even if ultrasonic waves are used together, the cleaning effect is reduced, or the cleaning agent attached to the object to be cleaned is There is a problem that a large amount is taken out and the cleaning liquid is consumed so much.

On the other hand, the commonly used toluene,
Aromatic hydrocarbon solvents such as xylene, benzene and their derivatives such as trimethylbenzene, methylethylbenzene and propylbenzene, and chlorine solvents such as 1,1,1-trichloroethane, trichloroethylene, methylene chloride and perchloroethylene are It is highly toxic to Japan and is subject to legal regulations in Japan such as the Industrial Safety and Health Act Organic solvent poisoning prevention rules. In addition, environmental pollution caused by scattering due to evaporation and mixing into drainage causes social problems. Therefore,
Considering the risk of handling this and its complexity, it is not preferable to use it as a cleaning liquid.

The present invention has been made in consideration of the above problems and is excellent in dissolving and cleaning pitch, wax, abrasives, grinding oil, protective film and the like, and is extremely safe for human body and environment. It is an object to provide a cleaning composition which is expensive and inexpensive. Another object of the present invention is to provide a cleaning method capable of excellent cleaning by using this cleaning composition.

[0008]

The cleaning composition of the present invention comprises:
It is composed of a mixed composition of benzyl acetate and a naphthene-based solvent, and is particularly characterized in that the mixing ratio of benzyl acetate and the naphthene-based solvent is 8: 2 to 2: 8. Here, benzyl acetate is represented by the following formula, wherein R is a methyl group or an ethyl group.

The benzyl acetate and naphthenic solvents used in the present invention do not cause environmental destruction such as ozone layer destruction because they do not contain halogen atoms such as chlorine and fluorine in the molecule. Further, benzyl acetate is used in soaps, cosmetics, food flavors, etc., and is highly safe for the human body. It is known that naphthenic solvents are also less toxic to the human body than chlorine-based solvents and aromatic solvents.

In terms of detergency, benzyl acetate has a good dissolving action on wax, but its dissolving action on pitch is slow depending on the type of pitch. Therefore, when cleaning an object to be cleaned to which both pitch and wax adhere, it takes some time to completely remove the pitch. However, when naphthenic solvent is mixed with benzyl acetate, the naphthenic solvent has a swelling and peeling action on pitch and wax. Pitches and waxes can be completely dissolved and removed in a shorter time than in the case of cleaning with a single composition, and good cleaning properties can be obtained.

In the mixed composition ratio of benzyl acetate and naphthenic solvent, when the object to be cleaned is pitched, benzyl acetate: naphthenic solvent = 4: 6 to
The range of 5: 5 is good. On the other hand, when the stains on the object to be cleaned are polar stains such as wax, the range of benzyl acetate: naphthene solvent = 8: 2 to 5: 5 is preferable.

Further, when the stain on the object to be cleaned is mild such as cutting oil, it can be cleaned with a mixed composition ratio of benzyl acetate: naphthene solvent = 2: 8 to 4: 6. Since the amount of low-cost naphthenic solvent increases, the cost of the cleaning composition can be suppressed. In addition,
By increasing the mixing ratio of the naphthene-based solvent, the dissolving power of the cleaning composition itself is lowered, but even in this case, it is sufficiently effective for mild dirt such as cutting oil.

In the cleaning composition of the present invention, a naphthenic solvent in a distillation range close to the flash point of benzyl acetate (eg, benzyl acetate: flash point 102 ° C.) (about ± 15 ° C. is good) is selected and mixed. Allows the flash point of the cleaning composition to be maintained at 85-110 ° C. Therefore, the cleaning composition becomes flame-retardant, and even if the cleaning composition is heated and used, it can be avoided from the risk of ignition and safety can be ensured. By heating the cleaning composition in this manner, stains such as pitch and wax adhering to the object to be cleaned can be softened and cleaned, so that the cleaning composition can be efficiently cleaned in a short time.

In cleaning, a physical force such as ultrasonic waves or a jet flow can be used in combination, and the physical force acts on the pitch and wax softened by heat, so that good cleaning property can be obtained in a short time. be able to. In particular, since the cleaning composition of the present invention has a low viscosity, it can exhibit the cavitation effect by ultrasonic cleaning and can be efficiently cleaned.

A general mixed composition cleaning composition comprises:
The composition of the cleaning composition collapses during regeneration by distillation or the like. For this reason, stable cleaning performance cannot be obtained, and it is difficult to recycle by distillation. However, in the cleaning composition of the present invention, the boiling points of both can be made extremely close by combining benzyl acetate and a naphthenic solvent having a close boiling point. As a specific example, when benzyl acetate (boiling point 125 ° C.) is used as benzyl acetate, a naphthene-based solvent having a distillation width close to this boiling point, specifically, a boiling point of 200
By combining a naphthene-based solvent selected from the range of up to 230 ° C., even if an azeotropic composition is not used, it becomes an approximate azeotrope and the composition can be recycled by distillation regeneration without changing the composition ratio. This makes it possible to obtain stable cleaning performance and at the same time be economical. Further, since the cleaning composition can be reused, the amount of industrial waste can be extremely reduced.

Although the cost of benzyl acetate is slightly high, the cost of the cleaning composition can be kept low by mixing it with a naphthenic solvent having a low unit price.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the following embodiments, benzyl acetate was selected as the benzyl acetate. On the other hand, the naphthene-based solvent to be mixed with this benzyl acetate is a cyclic saturated hydrocarbon represented by the general formula C _n H _2n (n is an integer) and has a boiling point of 190 to 240 ° C. Those having a boiling point (distillation range) close to that of the target benzyl acetate were selected. In the following embodiments, the naphthene-based solvent is naphthezol M.
(Manufactured by Nippon Petrochemical Co., Ltd.) was selected. Table 1 shows basic physical properties such as boiling points and flash points of the benzyl acetate and the naphthenic solvent.

[0018]

[Table 1]

(Embodiment 1) In order to confirm the cleaning properties of various pitches and waxes by the cleaning composition, slide glass coated with 0.13 mm of pitch and wax was added to each cleaning composition having the following mixing composition ratio. Soak for a minute,
The dissolved state of pitch and wax was confirmed. The liquid temperature of the cleaning composition was set to 40 ° C. No ultrasonic waves were used to confirm the solvency of the cleaning composition.

As the pitch, K1, K3, and K8 (all manufactured by Kuju Denki KK) were used as straight asphalt, and KB4 (manufactured by Kuju Denki KK) was used as blown asphalt. The wax is slot wax M,
Proof wax, yellow wax B, and sky wax M1 (both manufactured by Nikka Seiko Co., Ltd.) were used.

Immersion of slide glass in cleaning composition 30
After confirming the remaining state of pitch and wax after a minute,
It was evaluated by ranking E. A: No pitch or wax remained. Or, the pitch and wax are softened and flow, and it is likely to be removed immediately with a light physical force. B: Pitch and wax are softened or peeled off. C: Pitch and wax are slightly softened or swollen. D: A state in which a slight surface change was observed. E: No change and no dissolution phenomenon.

In addition, the comprehensive evaluation of cleaning is "◎",
It is represented by “◯”, “Δ”, and “x”. "◎" and "○" are
The evaluation shows that it has excellent cleaning properties in response to heavy dirt such as pitch and wax. The symbol “Δ” indicates that the cleaning property is slightly inferior, but the level is sufficiently effective when a small amount of pitch or wax is attached or when it is contaminated with cutting oil or the like. That is, even if the cleaning property is slightly inferior, it is economical and sometimes effective as a cleaning composition. “X” is an evaluation that has cleaning properties and cannot sufficiently remove target stains.

As the cleaning composition, benzyl acetate was used as benzyl acetate, and Naphthesol M was used as a naphthene-based solvent in a weight ratio of 8: 2, 6; 4, 5: 5, 4: 6,
It was adjusted by mixing at a mixing composition ratio of 2: 8. Pitch detergency and wax detergency when cleaning with this cleaning composition are shown in Table 2 and Table 3, respectively. For comparison, benzyl acetate,
The results of washing Naphthesol M alone are also shown in Tables 2 and 3.

As can be seen from these results, the cleaning composition in which benzyl acetate and a naphthenic solvent are mixed has a higher dissolving power due to the synergistic effect of the cleaning composition and the cleaning composition containing both pitch and wax, as compared with the cleaning composition cleaned with each of them alone. It was possible to dissolve, and it was possible to obtain good detergency.

In this embodiment, benzyl acetate was used as the benzyl acetate instead of benzyl acetate, and ethyl phenylacetate having an alkyl group as an ethyl group was selected and washed in the same manner.

[0026]

[Table 2]

[0027]

[Table 3]

(Embodiment 2) Benzyl acetate as benzyl acetate and Naphthesol M as naphthenic solvent
Was used at a weight ratio of 1: 1 and the liquid temperature of this cleaning composition was 25 ° C, 40 ° C, 50 ° C, 60 ° C, 8 ° C.
The washing was performed at 0 ° C. as in the first embodiment. The washing results are shown in Tables 4 and 5. However, the washing time was shortened by 15 minutes in order to make a significant difference. No ultrasonic waves were used as in the first embodiment. The residual state of the pitch and wax after 15 minutes of immersion was confirmed, and the evaluation was performed by ranking A to E as in the first embodiment. In addition, the comprehensive evaluation is shown by “⊚”, “◯”, “Δ”, and “x” similar to those in the first embodiment.

As can be seen from these results, as the temperature of the liquid of the cleaning composition becomes higher, the pitch and wax are softened and at the same time the dissolution rate is increased. Can be dissolved and washed at the same time.

[0030]

[Table 4]

[0031]

[Table 5]

(Embodiment 3) Benzyl acetate as benzyl acetate and naphthezol M as naphthene-based solvent
By using a cleaning composition in which the ratio of 1: 1 is mixed in a weight ratio of 1: 1 with or without ultrasonic cleaning, and the frequency of ultrasonic waves is low or
Cleaning was performed when a high frequency was used. Table 6 shows the results. As the frequency on the low frequency side, 28 KHz was used as a typical commercially available one. In addition, the frequency on the high frequency side is 40 as a typical commercially available one.
KHz was used.

As a cleaning sample, a lens (glass material FSL5, glass material FSL5, which has a pitch K1, an abrasive material, and a protective film (trade name "hard coat # 3", manufactured by Kuju Denki KK) attached thereto.
(Manufactured by Ohara Optical Glass Co., Ltd.) was used.

Cleaning is 28 KHz, 600 W or 40 K
The object to be cleaned was immersed in a cleaning machine equipped with an ultrasonic oscillator of 600 Hz and a frequency of 600 W (manufactured by Sun Denshi Co., Ltd.), and the time until the pitch and wax could be completely cleaned was measured.

When ultrasonic waves are used in combination, pitch and wax swelled and softened by the cleaning composition are easily separated and decomposed by the cavitation effect of ultrasonic waves, so that the cleaning can be performed efficiently and completely in a short time. You can Regarding the frequency of ultrasonic waves, the low frequency side (28 KHz) has a cleaning effect more than the high frequency side, and efficient cleaning is possible.

[0036]

[Table 6]

(Embodiment 4) Benzyl acetate and naphthezol M are selected, and the mixing ratio is 8: 2 to 2: 2 by weight.
The composition ratio before and after the distillation regeneration by the vacuum distillation apparatus was confirmed by adjusting in the range of 8. Table 7 shows the composition ratio of the cleaning composition before and after distillation.

As distillation conditions, the distillation temperature was 126 ° C. (heating vapor pressure 6 kg / cm ² ), and the degree of vacuum was −730 mmHg. As the vacuum distillation apparatus, a trade name “DC-31 (manufactured by Olympus Optical Co., Ltd.)” was used.

From Table 7, since the boiling points of benzyl acetate and naphthezol M are close to each other, a pseudo azeotrope is formed, and the composition ratio after distillation is at a level at which the detergency is not sufficiently affected, and reusable and reusable. There is.

[0040]

[Table 7]

[0041]

Industrial Applicability The cleaning composition of the present invention can efficiently clean and remove pitches and waxes used for processing lenses and prisms of optical parts from the composition. At the same time, cleaning of the abrasive, grinding oil, protective film, etc. can be performed. Furthermore, the cleaning composition of the present invention is extremely safe for humans without damaging the environment,
Effective cleaning can be performed in use. In addition, it can be reused and the amount of waste as industrial waste can be reduced.

In the cleaning method of the present invention, a physical force such as ultrasonic waves is applied to such a cleaning composition, so that the above-mentioned stains can be removed more efficiently.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C11D 7:24)

Claims (4)

[Claims] 1. A cleaning composition comprising a mixed composition of benzyl acetate represented by the formula (1) and a naphthene-based solvent. (R is a methyl group or an ethyl group.) 2. Benzyl acetate: naphthene-based solvent =
The cleaning composition according to claim 1, which has a mixed composition ratio of 8: 2 to 2: 8. 3. The liquid temperature of the cleaning composition according to claim 1 is 40.
A cleaning method comprising heating to -80 ° C and applying a physical force to the cleaning composition for cleaning. 4. The cleaning method according to claim 3, wherein one of ultrasonic waves on the low frequency side of 30 KHz or less, a jet stream, and heating is used as the physical force.