JPH0753998A - Degreasing cleaner - Google Patents

Abstract

PURPOSE:To obtain the cleaner having excellent degreasing and cleaning properties and high safety and working environmental health and being nonproblematic in environmental pollution by mixing a pyrrolidone with water and a nonionic surfactant. CONSTITUTION:The cleaner comprises 50-95wt.% pyrrolidone, 50-5wt.% water and 0.001-20wt.% nonionic surfactant. As the pyrrolidone, N-methyl-2-pyrrolidone is particularly desirable. As the nonionic surfactant, polyoxyethylene alkyl phenyl ether (desirably containing 2-15 moles of ethylene oxide added).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degreasing cleaning agent, and more particularly to a cleaning agent for oily deposits for efficiently cleaning and removing oil deposits on objects to be cleaned such as metal parts.

[0002]

2. Description of the Related Art When processing precision mechanical parts, electric parts, etc., various oils are used in the manufacturing process. Therefore, it is necessary to wash and remove oil adhering to the surfaces of various parts. Usually, an oil component is washed and removed using an organic solvent. Conventionally, as an organic solvent used for washing and removing such an oil component, a hydrocarbon solvent such as kerosene, benzene and xylene, a chlorine solvent such as trichloroethylene and tetrachloroethylene, and a freon solvent such as trichlorotrifluoroethane are known. ing. 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.

However, among the above-mentioned conventional organic solvents, hydrocarbon solvents, particularly benzene, xylene, etc., are highly toxic and are compounds designated as harmful substances under the Industrial Safety Law, and therefore, the work of handling them is difficult. There is a problem in terms of danger and complexity. Further, the chlorine-based or chlorofluorocarbon-based solvents have major problems in terms of safety, toxicity, environmental pollution and the like.

Therefore, in recent years, various degreasing detergents have begun to be proposed instead of conventional solvents. For example, Japanese Patent Laid-Open No. 4
Japanese Patent Publication No. 9-128908 discloses a cleaning composition containing N-methyl-2-pyrrolidone (hereinafter sometimes referred to as "NMP") and a surfactant as main components. Further, JP-A-4-68094 proposes a degreasing detergent containing NMP and a nonionic surfactant as main components.

[0005]

Pyrrolidone, especially NM
P itself has been a well-known solvent for a long time, and the above-mentioned detergent composition was added with a surfactant to improve the effect of dissolving NMP in oil. The detergent was repeatedly used for washing. The present invention solves the above-mentioned conventional problems and has excellent degreasing and cleaning properties for oils, and safety and working environment hygiene. It is an object of the present invention to provide a degreasing detergent having good properties and free from environmental pollution problems.

[0006]

Means for Solving the Problems The present inventors have solved the above-mentioned conventional problems, have excellent degreasing and cleaning properties for oils, have good safety and work environment hygiene, and have a problem of environmental pollution. The present invention has been achieved as a result of earnest studies for the purpose of providing a degreasing detergent free from depletion. That is, the degreasing detergent of the present invention is characterized by containing 50 to 95% by weight of pyrrolidone, 50 to 5% by weight of water, and 0.001 to 20% by weight of a nonionic surfactant.

The present invention will be described in detail below. The pyrrolidone used in the present invention is a liquid containing a pyrrolidone compound as a main component. Here, as the pyrrolidone compound, 2
-Pyrrolidone, 3-pyrrolidone, N-alkyl-2-pyrrolidone (for example, N-methyl-2-pyrrolidone, N-
Ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone), 5-alkyl-2-pyrrolidone (for example, 5-methyl-2-pyrrolidone, 5-ethyl-2-pyrrolidone,
5-propyl-2-pyrrolidone), N-vinyl-2-pyrrolidone, N-alkyl-3-pyrrolidone (for example, N
-Methyl-3-pyrrolidone, N-ethyl-3-pyrrolidone, N-propyl-3-pyrrolidone) and the like are exemplified, but N-methyl-2-pyrrolidone is particularly effective. The pyrrolidone compound may be used alone or in a mixture of two or more kinds.

The content of pyrrolidone in the degreasing detergent of the present invention is 50 to 95% by weight, preferably 70 to 85% by weight.
And 50 to 5% by weight of water, preferably 15
˜30% by weight.

When the content of water in the degreasing detergent is within the above range, the degreased oil component is easily floated and separated without being dissolved after the degreasing treatment, the mixture can be repeatedly used for a long time, and the entire amount of the mixture can be recovered. Or, it is preferable not only that it does not need to be replaced periodically, but especially when the water content is about 15% by weight or more, since the mixture does not catch fire, it can be handled as a non-hazardous material, which is preferable. When the content of water in the liquid mixture is less than 5% by weight, that is, when repeatedly used, the degreasing and cleaning effect is likely to be lowered because the oil has high solubility in a detergent. Further, if the water content of the mixture is more than 50% by weight, the degreasing and cleaning effect is significantly reduced.

Further, as an unexpected effect when the degreasing detergent is used as a mixed solution of pyrrolidone and water, the addition of water to pyrrolidone can remarkably suppress the generation of peroxide due to oxidation in the atmosphere. There are points. Since the cleaning agent is usually used repeatedly, suppressing the generation of such a peroxide is extremely advantageous in terms of stability of the performance as the cleaning agent.

The mixture of pyrrolidone and water is itself
Although it can be used as a degreasing detergent, the degreasing detergent of the present invention is characterized by obtaining a more excellent cleaning effect by containing a specific surfactant in the mixed solution.

That is, the degreasing detergent of the present invention further contains a specific amount of a nonionic surfactant in addition to pyrrolidone and water. Nonionic surfactants include polyoxyethylene stearyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ethers, polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether, and polyoxyethylene alkylphenyl ethers. Fluorine-containing nonionic surfactants such as oxyethylene fatty acid esters or amides, perfluoroalkyl group-containing ethylene oxide adducts, perfluoroalkyl group-containing oligomers and the like can be mentioned, but polyoxyethylene alkyl phenyl ether is preferable, and in this case The number of moles of ethylene oxide added is usually 1 to 30, preferably 2-1.
It is 5. The above nonionic surfactants may be used alone or in a mixture of two or more.

The content of the nonionic surfactant is 0.0
The content is 01 to 20% by weight, preferably 0.01 to 2% by weight. The effect of containing the additive is exhibited even in an extremely small amount of about 0.001% by weight, and the additive can be contained in a relatively wide range. However, if the content exceeds 20% by weight, no further improvement in the cleaning effect is observed, and there is a case where the oil content is emulsified and the adhered oil content increases, which is not preferable.

Further, in the cleaning agent of the present invention, other solvent may be contained in such a range that they do not adversely affect the cleaning agent to an undesired degree. Other solvents include alcohols, ethers, esters, aromatic hydrocarbons and alicyclic hydrocarbons. Further, in order to improve the cleaning effect, in some cases, an alkali metal or alkaline earth metal salt, an organic amine, an anionic or cationic surfactant may be contained, and other known antioxidants, You may include a rust preventive agent, a thickener, etc.

As a cleaning method using the degreasing detergent of the present invention, it is desirable to specifically adopt the following method, but the degreasing detergent of the present invention is not limited to the following method. It goes without saying that this is not what is done.

That is, first, the degreasing detergent of the present invention is used to wash the oil-deposited substance, which is the object to be washed, by various washing methods such as a dipping method, an ultrasonic washing method, a rocking method, and a spraying method.
A cleaning process is performed at a temperature of 00 ° C., preferably 40 to 80 ° C. to degrease and clean the oil component attached to the object to be cleaned. When adopting the dipping method for this degreasing cleaning, the cleaning effect can be further enhanced by bubbling air or nitrogen through the cleaning agent.

Then, the cleaning agent adhering to the degreased and cleaned object is blown off by blowing air or an inert gas such as nitrogen gas. As a result, the cleaning agent is recovered, and the loss of the cleaning agent due to cleaning is reduced as much as possible.
The amount of detergent dissolved by water washing in the next step is reduced as much as possible to reduce the burden of wastewater treatment. In this case, the amount of gas sprayed may be such that the cleaning agent adhering to the object to be cleaned is blown off and removed in a short time.

The object to be cleaned, which has been subjected to the cleaning agent removal treatment, is then cleaned with water to remove the cleaning agent still remaining on the surface. For this water cleaning, various cleaning methods such as a dipping method, an ultrasonic cleaning method, a rocking method, and a spray method can be adopted.

The object to be cleaned after washing with water is dried by removing the water adhering to the surface thereof by blowing air at room temperature or with heated air or an inert gas such as nitrogen gas to blow it off. As a result, the object to be cleaned can be degreased and cleaned extremely cleanly.

In the present invention, the objects to be cleaned, to which the oil content adheres, include electronic parts, electrical parts, precision machine parts, resin machined parts, precision parts such as optical parts, machine parts, automobile parts and Mainly used are metal parts such as jigs and tools used in the assembly process. Specifically, examples of electronic components include printed wiring boards, IC lead frames, capacitors, liquid crystal displays, and semiconductor materials. Examples of electric machine parts include parts such as a core for a coater, electric motor parts such as a magnet, a brush, and a housing. Bearings as precision machine parts,
Examples include sewing machine parts and machining parts. Examples of the optical component include a lens. Bearings as mechanical parts,
Gears, various machine parts, etc. may be mentioned. 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,
Examples thereof include jigs and tools handled in various processes such as molding, processing, assembly, and finishing.

Examples of the oil adhering to the object to be cleaned include fats and oils, machine oils, cutting oils, heat treatment oils, greases and the like.

[0022]

[Function] Pyrrolidone is remarkably excellent in degreasing and cleaning properties of oils and the like, but by using a mixture of pyrrolidone and water,
A cleaning agent that has excellent degreasing cleaning effect, can be used repeatedly over a long period of time, has good safety and work environment hygiene, does not pollute the environment, and has excellent performance stability. . However, the cleaning effect can be further enhanced by further adding a specific amount of a nonionic surfactant to such a mixed liquid of pyrrolidone and water. In particular, in objects to be cleaned such as metal parts having various shapes, it is generally difficult to completely clean the recesses such as blind holes in the objects to be cleaned, but with the cleaning agent of the present invention, penetration into such parts, Washing is also good.

[0023]

[Examples] Specific examples and comparative examples are given below,
The present invention will be described more specifically, but the present invention is not limited to the following examples unless it exceeds the gist.

Examples 1 to 10 169.8 g of N-methyl-2-pyrrolidone and 30.0 of water
0.2 g of each of the nonionic surfactants shown in Table 1 was added to and mixed with the mixed solution of g to prepare a uniform solution, and the degreasing detergent of the present invention was prepared. Next, the obtained degreasing detergent was put into a 500 ml washer having an air blowing tube at the bottom and heated to 60 ° C.

An aluminum test piece having blind holes with a diameter of 3 mm (depth 10 mm) at four locations, into which heat-treatment oil had been injected (oil injection amount: 185 mg), was immersed in this washer, and an air blowing pipe was used. Air was blown at a rate of 7 l / min. After 10 minutes, the test piece was taken out of the washing machine and immersed in 200 ml of water for 1 minute. Then, carbon tetrachloride 80
The test piece after washing was immersed in g, and ultrasonic waves were applied for 5 minutes to extract the residual oil content on the surface of the test piece, which was analyzed by an infrared spectrophotometer to determine the residual oil content. The results are shown in Table-1.

Comparative Example 1 For comparison, washing was carried out in the same manner as in Example 1 except that the nonionic surfactant was not added to the mixed liquid of N-methyl-2-pyrrolidone and water, and the same procedure was performed. The residual oil content was determined and the results are shown in Table-1.

[0027]

[Table 1]

[0028]

As described above in detail, according to the degreasing detergent of the present invention, it is possible to wash an object to be washed with oil to obtain a good washing-treated product. Moreover, the degreasing cleaning agent of the present invention has excellent durability of degreasing cleaning effect, can be repeatedly used for a long period of time, and has good safety and work environment hygiene, no environmental pollution, and stable performance. It has excellent properties and is extremely useful industrially.

Claims (1)

[Claims] 1. Pyrrolidone 50-95% by weight, water 50-
A degreasing detergent comprising 5% by weight and 0.001 to 20% by weight of a nonionic surfactant.