JPS5827318B2 - How to prevent metalworking oil from rotting - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for preventing corrosion of metal working oil.

BACKGROUND ART Conventionally, as a method of preventing metalworking oil from spoiling, organic disinfectants have been added to metalworking oil.

However, even if the anti-corrosion effect of this organic disinfectant is good against specific microorganisms, sufficient effects may not be obtained depending on the type of microorganism.

Therefore, when using the disinfectant, it was necessary to select an appropriate disinfectant in consideration of the type of target microorganism.

Furthermore, some organic disinfectants are themselves degraded by microorganisms, and their anti-septic effects necessarily last only for a short period of time, so disinfectants must be added frequently. There is a need to.

The present invention was completed as a result of intensive research to eliminate the drawbacks of the conventional methods.

The present invention is a method for preventing corrosion of metal working oil, which is characterized by adding 0.001 to 5.0% by weight of tin and/or germanium to water-soluble metal working oil.

When used, the water-soluble metalworking oil is diluted with water at an appropriate ratio, stored in a tank, etc., and circulated between the tank and the equipment used.

Therefore, the metal according to the invention is added when diluting the metal working oil with water.

Examples of metalworking oil include cutting oil, rolling oil,
Examples include heat-treated oil.

There are two types of cutting oil: emulsion type, which mainly consists of mineral oil, surfactant, rust inhibitor, and water, and soluple type, which mainly consists of large amount of surfactant, small amount of mineral oil, rust inhibitor, and water. There is an emulsion type.

In addition, heat-treated oils include, for example, those made of polyethylene glycol and water.

In addition, tin and germanium are used in the form of metal powder or metal salt, and examples of metal salts include SnSO4, G
Examples include eO2.

In the present invention, the amount of these metals added is determined taking into consideration the type of metal working oil to be used, the usage environment, etc., but is usually 0.001 to 5.0% by weight, preferably 0.01 to 1% by weight.
．． Adding 0% by weight will produce sufficient effects.

The metalworking oil obtained by adding tin and/or germanium according to the method of the present invention is placed in an oil tank and used for circulation in various equipment.

As mentioned above, metalworking oils obtained by adding organic fungicides using conventional methods have a short lifespan because the fungicides themselves are decomposed by microorganisms. It was necessary to add the fungicide.

On the other hand, the metalworking oil obtained by the method of the present invention is
Due to the long life of the disinfectant, there is no need to add the disinfectant as frequently as in the past.

Moreover, the metal used in the present invention has the advantage of exhibiting anti-corrosion effects against most microorganisms, regardless of the type of microorganisms, and is particularly effective against anaerobic bacteria and sulfate-reducing bacteria. Shows preventive effect.

Therefore, the method of the present invention is extremely useful in metal processing fields such as the automobile industry and the machinery industry.

Next, the present invention will be explained in detail with reference to examples.

Examples and Comparative Examples New metal working oil (20 times dilution with water) 2 (Bi
' was collected in a test tube, and 0. Ig, oil content ← sliding surface oil 0.1, F) and rotten oil of the metal working oil 0.
1. ? Add.

Next, add the specified amount of the fungicide shown in Table 2 to this to make 3
Static culture at 0℃, count of viable bacteria (cells/mC) at regular intervals
Measure.

Note that sliding surface oil is mixed into metal processing oil such as cutting oil during metal processing, and has the property of promoting the decomposition effect by microorganisms.

In addition, chips are metal powder produced by cutting during metal processing, and are mixed into metal processing oil.

When measuring the number of viable bacteria, the following culture medium is used for each type of bacteria.

(1) Aerobic bacteria (agar plate method) Medium composition: Meat extract O 65%, peptone 1.0%, sodium chloride 0.5%, agar 1.5% * (pH 7.0) (2) Anaerobic bacteria ( Modified VL basal medium) Medium composition: peptone 1.0%, yeast extract 0.5%, bart extract 0.14%, glucose 0.2%, potassium dihydrogen phosphate 0.045%, potassium hydrogen phosphate 0.045%, ammonium sulfate 0.09%, sodium chloride 0.09%, magnesium sulfate (anhydrous salt) 0.009%, calcium chloride (anhydrous salt) 0.09%, agar 15%, cysteine hydrochloride 0.03 %, sodium hydroxide 0.4% (pH 7.0) (3) Add 1.5% agar to sulfate-reducing bacterium Sfuky medium (American Type Culture Collection, No. 12L, page 331 (1976)). use.

Oil agents A-C in the following sides have the following meanings.

Oil agent A: Emulsion type cutting oil agent B: Soluple type cutting oil oil agent C: Emulsion type rolling oil Viable number of aerobic bacteria, anaerobic bacteria, and sulfate-reducing bacteria in each metal working oil before adding disinfectant (counts/ m is shown in Table 1.

Table 2 shows the measurement results of the number of viable bacteria when each disinfectant was added.

As is clear from the results in Table 2, the metalworking oil obtained by adding tin and/or germanium according to the method of the present invention exhibits an excellent anti-corrosion effect, especially against anaerobic bacteria and sulfate-reducing bacteria. It has a remarkable effect.

Claims (1)

[Claims] 1. A method for preventing spoilage of metal working oil, which comprises adding o, ooi to 5.0% by weight of tin and/or germanium to water-soluble metal working oil.