JPS5821956B2 - Water-soluble abrasive composition for ferrous metals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-soluble abrasive composition for ferrous metals.

More specifically, the present invention relates to a nitrite-free water-soluble abrasive composition for iron-based metals.

(Prior Art) Conventionally, compositions containing nitrite and alkanolamine as main components have been frequently used as water-soluble abrasives.

This composition has been widely used for grinding metals because it has excellent properties required for an abrasive, such as grindability, anti-rust properties, and antifoaming properties.

However, in recent years, the formation of nitrosamines due to the reaction between nitrites and alkanolamines in abrasives has been confirmed, and there have been concerns about carcinogenic effects based on this, and there has been a need for abrasives that are free from such risks. .

Furthermore, abrasives containing nitrites. Since the waste liquid is difficult to treat, it also causes problems in terms of pollution control.

Under these circumstances, various abrasives that do not contain nitrites have been tried in recent years, but no substitute for the nitrite-alkanolamine type has yet appeared.

For example, abrasives using phosphates as inorganic inhibitors instead of nitrites are not as good as those using nitrites in rust prevention and grindability.

Furthermore, when an alkali metal salt of an organic acid or other organic inhibitor is used instead of an inorganic salt, the anti-rust properties and/or anti-foaming properties are poor.

On the other hand, when grinding with a sulfur grindstone, a bad odor is generated.
As a measure to suppress the so-called 6-sulfur deterioration of grinding fluids, such as reduced grindability and the formation of rust, grinding agents are known that contain specific oxidizing agents and nitrites as essential components, and in some cases also contain aliphatic amines ( For example, Japanese Patent Application Laid-Open No. 140992/1983).

However, since nitrites and amines are still essential components, concerns about carcinogenic effects due to the formation of nitrosamines as described above have not been resolved.

(Objective of the invention) Given the current situation as described above, a water-soluble abrasive for ferrous metals that is free from the concern of producing nitrosamines and can be used practically in terms of grinding properties, rust prevention properties, and antifoaming properties. It is an object of the present invention to provide.

(Structure of the Invention) - As a result of intensive research to achieve the above object, the present inventors have discovered that a composition containing a water-soluble molybdate and an alkanolamine can be used as a water-soluble abrasive for iron-based metals. The present invention was achieved by discovering that it exhibits extremely excellent performance.

That is, the present invention is a water-soluble abrasive composition for iron-based metals containing a water-soluble molybdate and an alkanolamine as essential components.

In the present invention, iron-based metals refer to metals whose main component is iron, such as carbon steel, alloy steel, cast steel, and cast iron.

The water-soluble molybdates constituting the abrasive of the present invention include sodium molybdate, potassium molybdate,
Lithium molybdate, ammonium molybdate, etc. can be used, and as alkanolamines, ethanolamine (mono, di, and tri) and impropaturamine (mono, di, and tri) can be used. .

Moreover, two or more of these molybdates and alkanolamines may be used in combination.

Note that the water-soluble abrasive composition for ferrous metals of the present invention may also contain non-ferrous metal anticorrosives, preservatives, etc. as optional components in addition to the above-mentioned essential components.

The method for preparing and using the water-soluble abrasive composition for ferrous metals of the present invention can be based on the method for preparing and using conventional water-soluble abrasives.

That is, an aqueous solution is prepared by dissolving the essential components and optional components in an appropriate amount of water, and this is diluted with water before use.

The concentration of the essential components in use should be at least 1,00 opp for molybdate and at least 5,000 pIII for alkanolamine.

If the concentration is lower than this, sufficient grindability and rust prevention properties cannot be obtained.

The blending ratio of both is adjusted as appropriate depending on the grinding conditions and the type of material to be stiffened.

The thus obtained water-soluble abrasive composition for ferrous metals of the present invention has various performances such as grinding properties, rust prevention properties, and antifoaming properties that are equivalent to or better than nitrite-alkanolamine type abrasives. Since it does not produce any nitrosamines, there is no concern that it may cause cancer.

The following examples are provided to further specifically explain the present invention and are not intended to limit the present invention.

Example 1 The anti-rust properties, abrasive properties and defoaming properties of the composition of the present invention were compared with conventionally known abrasives and comparative samples.

(1) Samples A, B, C and D = Abrasive composition of the present invention' Sample E: Nitrite-alkanolamine type abrasive Sample F: Commercially available abrasive sample containing an inorganic salt as an inhibitor instead of nitrite G: Commercially available abrasive sample containing an organic acid salt as an inhibitor instead of nitrite H: Comparative sample consisting only of sodium molybdate and water ■ Comparative sample consisting only of nitriethanolamine and water Table 1 shows the composition of each sample. is expressed in weight%.

(2) Anti-corrosion properties Each of the abrasives used as samples was diluted with water and used at a component concentration of 1.0% by weight.

The testing methods used were a casting swarf immersion method and a mild steel plate eaves exposure method.

(a) Foundry chips immersion method Dry cut foundry chips G°C of approximately IFI -25.8 ~
12 meshes) were collected in a Petri dish (inner diameter approximately 60 mm), approximately 25 WLl of sample grinding material was added thereto, and after thorough shaking, the mixture was allowed to stand for approximately 10* minutes.

Next, the sample grinding fluid was removed by a decanting method, and the state of rust generated on the Petri dish was examined over time.

(b) Mild steel plate eave exposure method Clean mild steel plate polished with #240 sandpaper (5P
C-8D60 x 80 x 1.2 mm) was completely immersed in the sample diluent and then suspended under an eaves to examine the state of rust formation over time.

Table 2 shows the rust prevention test results.

It can be seen from Table 2 that the product of the present invention has the best rust prevention properties.

(3) Grindability Grindability was evaluated based on the grinding ratio.

Table 3 shows the test conditions, and Table 4 shows the measurement results of the grinding ratio.

The larger the number, the better the grindability.

It can be seen from Table 4 that the grinding ratio of the composition of the present invention is the best.

(4) Anti-foaming property 10A' of the abrasive agent listed in Table 1 was diluted with water to a component concentration of 1.0% by weight in an oil can, and the flow rate was 1.
The sample solution was forcibly circulated at a rate of 0.01/min, and the foaming height was measured every day.

Table 5 shows the foaming test results.

(Note) The method of displaying the results is as follows.

○ No foaming Δ Foam height: 5 cIfL or less × Foam height: 5 cIfL or more From Table 5, the antifoaming properties of the composition of the present invention should be comparable to that of nitrite-alkanolamine type E abrasives. I understand.

As shown by the above abrasive performance test results, the water-soluble abrasive composition for ferrous metals of the present invention is superior to nitrite-alkanolamine type, other conventional It has performance equivalent to or better than that of other abrasives.

Claims (1)

[Claims] 1. A water-soluble abrasive composition for iron-based metals containing a water-soluble molybdate and an alkanolamine as essential components.