JPH0665772A - Method for cleaning oil sticking material therefor - Google Patents

Abstract

PURPOSE:To clean and remove oil safely, sanitarily and efficiently to recover it by dipping a material to be cleaned in a detergent containing water and 2-pyrrolidone or the like and blowing gas thereto to separate the stuck oil to be floated and removed. CONSTITUTION:A material 10 to be cleaned such as metal parts stuck with oil on the surface is dipped in a washing tank 2 containing a detergent liquid 1. This detergent liquid 1 consists of water and one kind or more of 2- pyrrolidone, gamma-butyrolactone, and N,N-dimethylacetoamide, by about <=75wt.%, preferably 25-75wt.%. Air or nitrogen is blown into a cleaning tank 2 through a nozzle 5a of a spray header 5 disposed in the lower part of the tank 2. The gas blow rate is preferably 0.2-2Nl/min per one liter of the detergent liquid. Thereby, the stuck oil is removed and separated to float. The oil 8 is then recovered with an oil skimmer 6 or the like in an oil recovering tank 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning oil deposits, and more particularly to a method and apparatus for cleaning oil deposits for efficiently removing oil components adhering to objects to be cleaned such as metal parts. .

[0002]

2. Description of the Related Art In the cutting process of precision machine parts, electric parts, etc., the friction between the work material and the cutting tool is reduced, a large amount of frictional heat generated is removed, chips are washed away, and the life of the cutting tool is increased. Cutting oil, etc. is used for the purpose of extending the surface and smoothing the finished surface. Therefore, although these oils adhere to the processed material, it is often impossible to obtain a product if the oils remain adhered. For this reason, in the finishing process of such parts, oil components are usually washed and removed using an organic solvent.

Conventionally, as an organic solvent used for cleaning and removing such oil, hydrocarbon solvents such as kerosene, benzene and xylene, chlorine solvents such as trichloroethylene and tetrachloroethylene, and freon solvents such as trichlorotrifluoroethane. It has been known. In particular, CFC-based or chlorine-based solvents, which have characteristics of high cleanability and nonflammability, are used for electronic, electrical, mechanical and other parts.

[0004]

However, among the above-mentioned conventional organic solvents, hydrocarbon solvents, especially benzene,
Since xylene and the like are highly toxic and are compounds designated as harmful substances under the Industrial Safety Law, there are problems in terms of the danger and complexity of handling these. Further, the chlorine-based or chlorofluorocarbon-based solvents have major problems in terms of safety, toxicity, environmental pollution and the like. In addition, in the cleaning process of oily deposits, it is also important to efficiently remove the removed oil from the cleaning liquid.

The present invention solves the above-mentioned problems of the prior art, is excellent in degreasing and cleaning properties of oils, etc., has good safety and working environment hygiene, and has no problem of environmental pollution. It is an object of the present invention to provide a method and apparatus for cleaning oil-adhered substances, which makes it easy to recover the removed oil from the cleaning liquid.

[0006]

According to the method for cleaning an oil-adhered material of the present invention, at least the object to be cleaned having oil adhered to the surface is selected from 2-pyrrolidone, γ-butyrolactone and N, N-dimethylacetamide. When cleaning by immersing in a cleaning tank containing a cleaning agent containing one kind and water, a gas is blown into the cleaning tank to remove oil adhering to the object to be cleaned and to float and separate, This floating oil is separated and removed from the washing tank.

The apparatus for cleaning oil-deposited material of the present invention is at least selected from 2-pyrrolidone, γ-butyrolactone and N, N-dimethylacetamide for dipping and cleaning an object to be cleaned with oil adhering to the surface. A cleaning tank containing a cleaning agent containing one kind and water, a gas disperser provided in the lower part of the cleaning tank, and a means for supplying gas to the gas disperser. Blow into the cleaning agent,
It is characterized by comprising a gas introduction device for promoting the removal of oil content adhering to the object to be cleaned and the floating separation of the oil content, and an oil removal device for separating and removing the floating oil content from the cleaning tank.

The present invention will be described in more detail below. As the degreasing detergent used in the present invention, a mixture containing water in at least one selected from 2-pyrrolidone, γ-butyrolactone and N, N-dimethylacetamide is used. As the above mixture, water can be added to the above compound usually up to about 75% by weight, preferably 25 to 75% by weight. Especially in the case of 2-pyrrolidone or γ-butyrolactone, water is usually used
It is suitable to contain 5% by weight, preferably 35 to 60% by weight. In the case of N, N-dimethylacetamide, water is added in an amount of usually 25 to 75% by weight, preferably 25 to 75% by weight.
It is preferable to contain 60% by weight. After the degreasing treatment, the above compound containing water in the above range can be floated and separated without dissolving the oil, so that the washed product can be repeatedly used without recovering the entire amount of the detergent or periodically replacing it. Good, and since the cleaning agent does not catch fire, it can be handled as a non-hazardous material, which is preferable.

The amount of water in the mixture is 75% by weight.
If it is more, the degreasing effect is significantly reduced. Further, the cleaning agent used in the present invention contains a small amount of an alkali compound to improve the peeling effect of the coating film and to obtain a more excellent cleaning effect. In this case, the blending amount of the alkaline compound is 100 ppm or more in the concentration in the detergent, particularly 300 to
It is preferably set to 5000 ppm. Examples of the alkaline compound to be blended include alkali metal or alkaline earth metal hydroxides, carbonates, acetates and the like, as well as organic amines and the like, and preferably alkali such as sodium hydroxide and potassium hydroxide. It is a hydroxide of a metal or a hydroxide of an alkaline earth metal such as calcium hydroxide.

In the method for cleaning oil deposits of the present invention, when the oil deposits are immersed in a cleaning tank containing a detergent containing such a compound for cleaning, a gas is dispersed and introduced into the cleaning tank. This can be easily carried out by continuously and continuously separating and removing the oil component, which is separated from the object to be cleaned by the introduction of gas and is floated and separated, outside the cleaning tank. There is no particular limitation on the method for separating and removing the oil component floating in the cleaning tank, and generally, it can be easily carried out using an apparatus such as an oil skimmer apparatus or an overflow apparatus. Specifically, for example, the following method can be adopted.

That is, a header capable of blowing gas is provided at the bottom of the cleaning dipping tank having a temperature control function, and an appropriate blowing nozzle is attached to the header. The installation posture, the number of arrangements, and the arrangement positions of the header and the nozzle are selected so that the blown gas directly hits the object to be cleaned. The amount of gas blown out is sufficient for both physically removing the oil that adheres to the object to be cleaned and improving the contact between the cleaning agent and the object to be cleaned and chemically removing the oil. What is achieved is. It depends on the shape and size of the object to be cleaned and cannot be generally stated, but it is effective to increase the linear velocity of the gas ejected from the gas nozzle as much as possible. Air, nitrogen, or the like is suitable as the gas to be blown out. Normally, the amount of gas blown is 0.2 to 2 normal liters (N) per liter of the cleaning agent.
1) / minute is preferable.

In the present invention, the object to be cleaned is immersed in such a cleaning immersion tank containing the above-mentioned cleaning agent for cleaning treatment. At that time, the cleaning treatment temperature is 20-100.
C., especially 40 to 80.degree. C. are preferred. The oil component peeled and removed from the object to be cleaned by the immersion cleaning floats up in the cleaning immersion tank, and therefore it is preferably continuously subjected to density difference separation. In the present invention, in the density difference separation, the bubbles are introduced by gas blowing, so that the density of the oil component attached to the bubbles is reduced, and the oil component is more easily floated. Therefore, from this point as well, it is effective in terms of levitation separation that the amount of gas blown in is large, but if the amount of gas blown in is adequate to remove oil from the object to be cleaned, it is effective in levitation separation. A sufficient amount of gas is secured.

The oil component thus floated is separated and removed by the above-mentioned oil skimmer device, overflow device, etc., and discharged to the outside of the tank. This makes it possible to prevent the floating oil from reattaching to the object to be cleaned when the immersed object to be cleaned is taken out. At that time, the detergent used in the present invention dissolves the oil until it reaches saturation, but its saturation solubility is low. For this reason, the oil that becomes supersaturated and is discharged can be easily separated from the cleaning liquid.

[0014] In other organic detergent systems, energy is required to separate the once dissolved oil and the detergent, and density difference separation is impossible. On the other hand, with water-based cleaning agents, density difference separation is possible, but after cleaning, there is a problem of rusting of the object to be cleaned and a problem of corrosion of the cleaning liquid (water), and the effect of removing adhered oil is also sufficient It is not industrially disadvantageous because it is not.

The method for cleaning oily deposits of the present invention as described above can be easily carried out by an apparatus for cleaning oily deposits as shown in FIG. FIG. 1 is a sectional view showing a cleaning apparatus suitable for carrying out the method for cleaning oily deposits of the present invention. The illustrated cleaning apparatus includes a cleaning tank 2 for containing a cleaning liquid 1, a net cage 3 for suspending an object to be cleaned 10, a heat medium inlet 4A and an outlet 4B for adjusting the temperature of the cleaning tank 2. Jacket 4 having a spray nozzle, a spray header 5 provided with a spray nozzle 5A for a gas such as air or nitrogen, an oil skimmer device 6 for separating and collecting the floating oil component in the cleaning liquid 1, and an oil component. It is mainly composed of a recovery tank 7.

In order to clean the object 10 to be cleaned using the apparatus shown in the drawing, the object 10 to be cleaned having oil on its surface is put in the net basket 3 and lowered to remove the above compounds in the cleaning tank 3. Immerse it in the cleaning liquid 1 containing it. Then, air or nitrogen gas is blown from the lower part of the tank through the spray header 5 by the spray nozzle 5A to be dispersed, and the adhered oil component is peeled off so that the gas dispersion flow hits the object to be cleaned 10.

The oil 8 separated from the object to be cleaned 10 and floated above the cleaning liquid 1 is separated by the oil skimmer device 6 together with some cleaning liquid, and is recovered in the oil recovery tank 7. The recovered oil liquid 9A and the recovered cleaning liquid 9B recovered in the oil recovery tank 7 are treated according to a conventional method and reused as necessary. The recovered cleaning liquid 9B can be returned to the cleaning tank 3 as it is.

After the oil is removed in this manner, the article to be cleaned 10 is pulled up. And if necessary,
Wash with water and dry. Since the oil 8 is floated and removed from the cleaning liquid 10, the cleaning liquid 10 can be used for many batch cleanings over a long period of time. In addition, the cleaning method by the illustrated device is
It is one embodiment of the present invention, and the present invention is not limited to the illustrated method insofar as it does not exceed the gist thereof. For example, at the time of cleaning, fine ones are put in a net basket as shown in the drawing, and large ones can be directly washed without putting them in the net basket. Further, even in the immersion method, it is possible to provide a fixing metal fitting inside the cleaning tank, and fix the object to be cleaned to this for the purpose of selection. Further, as for the separation and removal method of the floating oil component, an oil skimmer device, an overflow method, and others can be adopted, and the heating method of the cleaning tank can be a steam method in addition to the heat medium method shown in the drawing. Various types such as a direct heating method can be adopted.

In such a method of the present invention, the object to be cleaned to which the oil content is attached is an electronic part, an electric part, a precision machine part, a resin machined part, a precision part such as an optical part, or a mechanical part. , Automobile parts and jigs and tools used in the assembly process thereof. Specifically, examples of electronic components include printed wiring boards, IC lead frames, capacitors, liquid crystal displays, and semiconductor materials. As electric parts, parts such as coater cores,
Examples thereof include electric motor parts such as magnets, brushes, and housings. Examples of precision machine parts include bearings, sewing machine parts, and processing parts. As an optical component,
Examples include lenses. Mechanical parts include bearings, gears,
Examples include various mechanical parts. Examples of automobile parts include engine parts, transmission gears, and carburetors. Further, as jigs and tools used in the assembling process of such parts, the above precision parts are manufactured, molded,
Examples include jigs and tools that are handled in various processes such as processing, assembly, and finishing.

Examples of the oil adhering to these objects to be cleaned include fats and oils, machine oils, cutting oils, greases and the like.

[0021]

The above-mentioned compounds are excellent detergents for degreasing and cleaning oils and the like, and having good safety and hygiene of the working environment and no environmental pollution. When dipping and cleaning the object to be cleaned with such a cleaning agent, the adhering oil component can be efficiently peeled and removed by blowing gas into the cleaning tank.

Thus, the peeled oil is efficiently floated in the cleaning liquid together with the bubbles of the blown gas, and the density difference can be easily separated. This utilizes the specific characteristics of the above-mentioned compound used as a cleaning agent in the present invention, which is an organic solvent infinitely soluble in water, peels oil, and floats without being dissolved. is there. That is, as described above, the above-mentioned compound dissolves the oil component until it becomes saturated, but its saturated solubility is low, so that the supersaturated oil component can be discharged and easily separated.

In the present invention, by utilizing such properties peculiar to the above-mentioned compounds and combining the gas blowing immersion cleaning method, the oil content can be easily and efficiently removed from the oil-adhered object to be cleaned in a short time. It was possible to remove the oil component from the cleaning liquid easily, as well as to remove the oil component from the cleaning liquid. According to the present invention, it is possible to remove the oil component in almost the same cleaning time as in the case of using the conventional trichloroethane-based cleaning agent, and moreover, since the oil component can be easily floated and separated, the treatment of the cleaning waste liquid is facilitated. To be done. By the way, in the case of a trichloroethane-based detergent, it is industrially disadvantageous because a complicated treatment such as an oil recovery treatment of the entire amount of the washing waste liquid or periodic replacement of the washing liquid is required.

[0024]

[Examples] Specific examples and comparative examples are given below,
The present invention will be described in more detail. Examples 1 to 4 Test pieces of the materials shown in Table 1 (2.98 cm x 4.9)
20 pieces (8 cm × 0.3 cm thickness) were randomly placed in a wire netting basket, immersed in cutting oil, and then pulled up.

FIG. 1 containing a cleaning agent containing a mixture of γ-butyrolactone (GBL) and water and having the composition shown in Table 1.
The above 20 test pieces together with the basket were immersed in the cleaning tank of the apparatus shown in FIG. The liquid temperature of this cleaning tank is 70 ° C.
After soaking for the time shown in Table-1, the test piece was taken out together with the basket. In addition, during immersion cleaning, blow air,
It was carried out at a rate of 0.63 Nl / min per liter of cleaning agent, and the floating oil component was separated and collected by an oil skimmer device. After this test piece was washed with water and dried, the residual state of oil on the surface was visually observed and evaluated. In addition, a cellophane tape was attached to the test piece, and the adhesiveness was examined, and the presence or absence of stains when the surface of the test piece was rubbed with a white cloth was also examined. The results are shown in Table-1.

Examples 5 to 6 The test pieces were washed in the same manner as in Examples 1 to 4 except that the detergents and compounds shown in Table 1 were used. Table-
Shown in 1.

Comparative Examples 1 to 4 The test pieces were washed in the same manner as in Examples 1 to 4 except that air was not blown in,
The evaluation results of the cleaning effect are shown in Table-1.

Comparative Example 5 The test piece was cleaned in the same manner as in Example 3 except that 1,1,1-trichloroethane was used as the cleaning agent, and the cleaning effect evaluation results are shown in Table 1. .

[0029]

[Table 1]

From Table 1, it is clear that the method of the present invention can efficiently remove the adhering oil component by washing in a short time. Such an effect of the present invention is an effect obtained by adopting a specific cleaning agent and a cleaning method. Even when the cleaning method is the same, the cleaning agent is different (Comparative Example 5) or the cleaning agent is the same. However, when the cleaning method is different (Comparative Examples 1 to 4), such excellent effects cannot be obtained.

[0031]

As described above in detail, according to the method for cleaning oily deposits of the present invention, the effect of degreasing and cleaning of oil components is excellent, the safety and the working environment hygiene are good, and there is no risk of environmental pollution. By using a good cleaning agent, it is possible to efficiently wash the object to be washed with oil and obtain a good washed product, and to efficiently remove the oil that has been washed and removed from the object to be washed. It is possible to reduce the processing work of the cleaning waste liquid and the processing cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a cleaning device suitable for carrying out a method for cleaning oily deposits of the present invention.

[Explanation of symbols]

 1 Cleaning Liquid 2 Cleaning Tank 3 Net Basket 5 Spray Header 5A Spray Nozzle 6 Oil Skimmer Device 7 Oil Recovery Tank 10 Cleaning Object

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[Procedure amendment]

[Submission date] October 9, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The header and nozzle provided at the bottom of the cleaning tank are designed so that the blown gas directly hits the object to be cleaned.
It is preferable to select the installation posture, the number of arrangements, the arrangement positions, and the like. In this case, the amount of gas blown out has both the effect of physically removing the oil component adhering to the object to be cleaned and the effect of chemically removing the oil component by improving the contact between the cleaning agent and the object to be cleaned. Any effect can be achieved. It depends on the shape and size of the object to be cleaned and cannot be stated in general.
It is effective to increase the linear velocity of the gas ejected from the gas nozzle as much as possible. Air, nitrogen or the like is suitable as this gas. In a normal case, the amount of gas blown is 0.2 to 20 normal liters (N) per liter of the cleaning agent.
1) / minute is preferable.

Claims (2)

[Claims] 1. A cleaning tank containing a cleaning agent containing at least one selected from 2-pyrrolidone, γ-butyrolactone and N, N-dimethylacetamide and water is placed on the object to be cleaned having oil adhered to the surface thereof. In the immersion and cleaning, a gas is blown into the cleaning tank to remove the oil component adhering to the object to be cleaned and to float and separate, and then the floating oil component is separated and removed from the cleaning tank. The method for cleaning oil deposits. 2. A cleaning tank containing a cleaning agent containing water and at least one selected from 2-pyrrolidone, γ-butyrolactone, and N, N-dimethylacetamide for cleaning an object to be cleaned having oil on its surface, It consists of a gas disperser provided in the lower part of the cleaning tank and a means for supplying gas to the gas disperser. The gas is blown into the cleaning agent from the gas disperser to remove oil adhering to the object to be cleaned. And a gas introduction device for promoting floating separation of the oil component, and an oil removing device for separating and removing the floating oil component from the cleaning tank.