JPH09165600A - Water-based detergent and cleaning using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-based detergent and to provide a cleaning method using the same, improved in adaptability to oil kind so as to be adaptable to broader range of oil kinds. SOLUTION: This water-based detergent is obtained by blending a cationic surfactant in a detergent consisting manly of a nonionic surfactant and a builder which is an inorganic salt with its valence of 1:1 type such as NaCl, NaHCO3 or KBr. The proportion of the builder to be blended is pref. 0.05-2.0 (esp. 0.2-0.8)mol per L of the final detergent. The objective cleaning method is such method that a cleaning liquid is prepared by diluting this detergent with water, and a used cleaning liquid contaminated with oil-and-fat is heated to a temperature higher than the cloud point of this detergent to allow the oil-and-fat in the used cleaning liquid to float up and separate it from the liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based cleaning agent and a cleaning method using the same, and in particular, in the manufacturing process of industrial products such as metal parts, semiconductor wafers, glass and liquid crystals The present invention relates to a cleaning agent and a cleaning method used in a water-based cleaning process for cleaning and removing dirt (oil, dust, burr, etc.).

[0002]

2. Description of the Related Art Freon and trichloroethane, which are chlorine-based organic solvents that have been widely used as industrial detergents, are
Since it was confirmed to be an ozone-depleting substance, it was discontinued by 1995 under international agreement. Freon
There is an urgent need to develop alternative cleaning agents for trichloroethane, but water-based cleaning agents containing surfactants and alkalis as the main ingredients,
Semi-aqueous detergents in which water is mixed with an organic solvent such as alcohol or glycol ether, and non-aqueous detergents represented by hydrocarbon solvents are becoming mainstream. However, in the case of non-aqueous cleaning agents, the cleaning costs are high because they are cleaned with the cleaning agents themselves, and because most of them are flammable substances, the cleaning equipment requires explosion-proof specifications, which makes them expensive or large. I have a difficulty that I can not do it.

On the other hand, in the case of a semi-water system, especially a water system, since the cleaning agent is diluted with a large amount of water and used, the running cost is low, and since it is not a hazardous substance, the cleaning device can be easily enlarged. , Relatively cheap. However, the use of a large amount of water has a problem that a water treatment system that can deal with oil-water separation of a washing liquid and wastewater treatment of rinse water becomes an integral part of the washing system. When an object to be cleaned is cleaned using a water-based cleaning agent, dirt such as oil content from the object to be cleaned gradually accumulates in the cleaning liquid along with the cleaning, and the cleaning power of the cleaning liquid decreases. As a matter of course, in order to extend the service life of the cleaning liquid while maintaining the cleaning power of the cleaning liquid, it is necessary to constantly remove dirt such as oil from the cleaning liquid.

Conventionally, the oil-water separation method of the water-based cleaning liquid has been carried out by destructing the emulsion using a chemical such as an emulsion breaker.
There are a floating separation method, an electrostatic separation method, a coalescer method for promoting coalescence and coarsening of oil particles, and a membrane separation method using a microfiltration membrane or an ultrafiltration membrane. Furthermore, the inventors previously used an aqueous detergent prepared by blending a nonionic surfactant having a cloud point of 40 to 70 ° C. with a nonionic surfactant having a cloud point of 20 to 40 ° C. As a result, the present invention has invented a water-based cleaning agent capable of floating and separating oils and fats in a cleaning liquid by simply heating the cleaning liquid containing the oils and fats to a temperature above the cloud point of the cleaning agent, and an oil-water separation method thereof.

However, each of these conventional techniques has problems. For example, in the emulsion destruction / floating separation method using an emulsion breaker, there is a problem that the cleaning liquid after oil separation loses cleaning power and cannot be reused. Further, in the electrostatic separation method or coalescer method, when the oil content in the cleaning liquid exists as fine emulsion particles, it is difficult to obtain the oil-water separation effect. Further, the microfiltration membrane and ultrafiltration membrane methods have a problem that the cleaning agent component is removed at the same time as the oil component and that the apparatus is expensive. The water-based cleaning agent developed by the inventors and the heating-type oil-water separation method to which the cleaning agent is applied are simple and inexpensive oil-water separation technologies that solve the above-mentioned problems of the prior art. There was some oil that I couldn't. That is, examples of the oil species that cannot be applied include oil species in which a large amount of an anionic surfactant such as calcium sulfonate is blended as a rust preventive.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, improves the applicability to oil species, and provides an aqueous detergent and a washing method applicable to a wider range of oil species. Is an issue.

[0007]

In order to solve the above problems, the present invention is characterized in that a detergent containing a nonionic surfactant and a builder as a main component is mixed with a cationic surfactant. It is a water-based cleaning agent. The nonionic surfactant to be used may be any of polyoxyethylene alkylphenyl ether type, polyoxyethylene alkyl ether type, polyethylene glycol type, sorbitan fatty acid ester type, polyoxyethylene sorbitan fatty acid ester type and pluronic type.
Further, the cloud point temperature of such a nonionic surfactant is
It may be in the range of 20 to 70 ° C, but a nonionic surfactant having a cloud point of 40 to 60 ° C and a nonionic surfactant having a cloud point of 25 to 30 ° C are used in combination. Is preferred.

In the above detergent, the builder is an inorganic salt having a valence of 1: 1 and the compounding ratio thereof is detergent 1
It is 0.05 mol or more and 2.0 mol or less, preferably 0.2 mol or more and 0.8 mol or less per liter. Further, in the present invention, in a cleaning method using a cleaning liquid obtained by diluting the above-mentioned aqueous cleaning agent with water, the cleaning liquid containing the oil and fat after cleaning is heated to a temperature not lower than the cloud point of the cleaning agent to float the oil and fat in the cleaning liquid. The cleaning method is characterized by separation.

[0009]

Next, the present invention will be described in detail.
The present invention clarifies the mechanism of the effect of anionic surface active substances such as calcium sulfonate compounded in fats and oils on the oil-water separability of the cleaning liquid, and by adding a cationic surfactant to the cleaning agent, It was made by discovering that the influence of surface-active substances can be suppressed. When degreasing cleaning is performed on a metal part or the like using a cleaning liquid containing a nonionic surfactant and a builder as main components, oil is emulsified by the nonionic surfactant and dispersed in the cleaning liquid. When the cleaning liquid containing the emulsified oil is heated above the cloud point temperature of the nonionic surfactant, the emulsified oil is demulsified and the oil is floated and separated. However, when an anionic surface-active substance, especially calcium sulfonate or barium sulfonate, is mixed in the oil component, a part of the substance is eluted in the washing liquid.

This results in an increase in the cloud point of the nonionic surfactant in the cleaning liquid and an increase in the emulsification of oil by the anionic surfactant. When the cloud point of the cleaning agent rises above the set heating temperature of the oil-water separator or when the amount of oil emulsified by the anionic surface-active substance increases, the oil-water separation mechanism by heating to the set temperature cannot function. The present invention, as a countermeasure against anions,
An attempt was made to add a suitable amount of cationic surfactant to the detergent in advance. As a result, it was confirmed that the cation and the anion are bonded to each other by the reaction to form an insoluble compound, whereby the anion loses the surface activity and the effect of the anion is suppressed. It was also confirmed that there is no inconvenience due to the addition of the cationic surfactant to the detergent. The cationic surfactant used in the present invention is preferably a quaternary ammonium salt or an imidazoline type cationic surfactant, and the compounding ratio is determined by the anion content of the oil species to be applied, but the weight ratio is And may be in the range of 0.2% to 2.0%.

As the builder to be added to the detergent, inorganic salts having a valence of 1: 1 are suitable, and examples thereof include sodium hydrogen carbonate, sodium chloride, sodium bromide, potassium hydrogen carbonate, potassium chloride and potassium bromide. These may be used as a mixture. The compounding ratio of the builder is preferably 0.05 mol or more and 2.0 mol or less, preferably 0.2 mol or more and 0.8 mol or less, per liter of the detergent. Other types of inorganic salts, for example having a valence of 1: 2
When sodium sulfate of the type is used, there is a concern that the sulfate ion, which is a divalent anion, will react with the cationic surfactant and inhibit the reaction between the cationic surfactant and the anionic surfactant. Requires attention. Also, primary amines such as ethanolamine, secondary amines such as diethanolamine, tertiary amines such as triethanolamine, and quaternary ammonium salts can be used as the alkaline organic builder.

[0012]

The present invention will be described below in more detail with reference to examples. Example 1 15% of a polyethylene alkyl phenyl ether type nonionic surfactant having a cloud point temperature of 49 ° C., 6% of a pluronic type nonionic surfactant having a cloud point temperature of 27 ° C., and an imidazoline type cationic surfactant. An aqueous solution containing 1% and 3.5% sodium hydrogen carbonate was prepared as a cleaning agent. The cleaning agent was diluted to 5% with water and used as a cleaning solution. The pH of the washing solution was 8.8. Further, as the oil type to be tested, an emulsion type water-insoluble oil rust preventive oil was used, and the oil concentration in the cleaning liquid was set to 2%. Barium alkyl sulfonate is mixed in a large amount as rust preventive oil in the rust preventive oil. It should be noted that, in order to make the oil-added cleaning liquid a stable emulsified state, it was vigorously stirred with a household mixer for 2 minutes.

1 liter of the washing solution thus prepared was transferred to a graduated cylinder, and the graduated cylinder was heated to 6 liters for heating.
It was placed in a constant temperature water bath at 5 ° C. Then, after 5 minutes of heating, oil began to float, and after 10 minutes, 18 ml, or 9
0% of oil surfaced. On the other hand, the detergent component settled to the bottom. In this way, by adding a cationic surfactant to a detergent containing a nonionic surfactant as a main component, it is possible to separate oil-water from emulsified water-insoluble oil that could not be separated from oil-water by the heating method. Became.

Comparative Example 1 Further, in order to further clarify the effect of the present invention, an oil-water separation test was carried out under the same conditions as those of the Examples, in the case where the detergent of the Examples was not blended with a cationic surfactant. Heat up 6
Even after 0 minutes, no oil floating was observed.

[0015]

When a cationic surfactant is added to the cleaning agent, the added cationic surfactant and the anionic surface active substance eluted from the fat and oil into the cleaning solution undergo a binding reaction,
It becomes an insoluble compound. Thereby, the adverse effect of the anionic surface-active substance on the oil-water separation method of the cleaning liquid is suppressed. As described above, in the present invention, by adding the cationic surfactant to the detergent, the detergent and the heating method of separating oil / water can be applied to the oil species containing the anionic surfactant. As a result, the range of application of the cleaning agent can be expanded.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C11D 7:10 1:38)

Claims (3)

[Claims] 1. A water-based detergent comprising a detergent mainly composed of a nonionic surfactant and a builder, and a cationic surfactant. 2. The builder is an inorganic salt having a valence of 1: 1 and the compounding ratio thereof is 0.05 mol or more and 2.0 mol or less per liter of the cleaning agent. The water-based cleaning agent according to claim 1. 3. A cleaning method using a cleaning solution obtained by diluting the cleaning agent according to claim 1 or 2 in a cleaning solution by heating the cleaning solution containing oil and fat after cleaning to a cloud point temperature of the cleaning agent or higher. A method for cleaning, characterized in that the oil and fat of the above is floated and separated.