JPS595670B2 - metal cleaning agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal cleaning agent, and more particularly to a water-soluble metal cleaning agent containing condensed ammonium phosphate as a main component and urea or a modified component thereof as an auxiliary component.

A wide variety of research has been conducted on metal cleaning agents, and currently there are alkaline cleaning agents based on petrochemical surfactants and inorganic bases, and acidic cleaning agents based on inorganic or organic acids. developed and commercially available.

However, looking at these commercially available products, there is no one that shows a universal cleaning effect on various metals, and many of the products with strong cleaning effects corrode the metal base material itself.
Furthermore, petrochemical-based cleaning agents have a high foaming property, so they are viewed as a problem in relation to wastewater pollution and the like. As described above, the reality is that there is currently no cleaning agent for metal surfaces that is satisfactory in terms of cleaning effectiveness, low corrosion, work safety, and non-polluting properties. As a result of intensive research to eliminate the above-mentioned drawbacks, the present inventor has found that an aqueous solution containing condensed ammonium phosphate as a main component and urea or its modified components as an auxiliary agent can remove complex adhering dirt on metal surfaces.
We found that this aqueous solution can effectively clean and remove adsorbed substances and metal oxidized corrosive substances, and further discovered that this aqueous solution is an excellent metal cleaning agent in terms of toxicity, safety, and non-pollution. , we have arrived at the present invention.

The details of the invention will be described below. The condensed ammonium phosphate which is the main ingredient of the cleaning agent of the present invention may generally be condensed ammonium phosphate obtained by a condensation reaction between orthophosphoric acid and urea, primary ammonium phosphate and urea, phosphoric anhydride and ammonia, etc. Its degree of condensation is from 3 to 150, preferably
It is 5-110.

If the degree of condensation exceeds 150, it will not dissolve even at a liquid temperature of 90° C. or higher and will form a slurry, making it difficult to exhibit its effectiveness as a cleaning agent main ingredient. On the other hand, if the degree of condensation is less than 3, not only will the cleaning effect on metals be reduced, but metal corrosive effects will even occur. As the urea modification component that should coexist with condensed ammonium phosphate, biuret or triuret is suitable, and these, including urea,
As a buffer for condensed ammonium phosphate on metal substrates,
It also acts as a pH adjuster for liquids.

These adjuvants are used alone or in combination with condensed ammonium phosphate. The ratio of condensed ammonium phosphate to urea or its modified component is 2:1 to 1 by weight.
A range of 0:1 is suitable, and a range of 3:1 to 6:1 is particularly preferred. If this ratio exceeds 2:1,
On the other hand, if the ratio is less than 10:1, the effectiveness as a metal cleaning aid decreases and the corrosivity to metal substrates increases. The cleaning agent according to the present invention is
When using, dissolve in water.

A suitable concentration is 1 to 50 weight percent, preferably 20 to 40 weight percent, based on water. When the concentration is less than 1% by weight, the cleaning effect is significantly reduced, a long cleaning time is required, and workability is deteriorated. On the other hand, if the concentration exceeds 50% by weight, the solubility of attached dirt such as attached scale or metal oxidized corrosives in the cleaning solution will be significantly reduced, and as a result, the metal cleaning effect will be reduced. On the contrary, it reduces work efficiency. The liquid temperature of the cleaning agent during the cleaning process can vary over a wide range, but is preferably in the range of room temperature to 90°C from the viewpoint of workability and the state of adhesion of dirt to the metal surface.

When using a processing liquid temperature of 90° C. or higher, the cleaning liquid itself boils, so an open type cleaning tank is used*: (This is not possible, so a closed type pressure tank must be used.

The metal cleaning agent of the present invention can be applied to general metal materials such as iron, aluminum, copper, stainless steel, various alloys, and special steel, as well as processed products made from these materials. It exhibits effective cleaning ability for metal materials to be cleaned, when the dirt is corrosive, scale, dirt, oil, etc. alone or in combination.

The toxicity of the metal cleaning agent according to the present invention is very low, and the pH of the cleaning agent aqueous solution is neutral between 6.5 and 7.5.
It is easy to handle and safe.

In addition, COD (Chemical Oxygen Demand), which is a drainage problem,
and BOD (biochemical oxygen demand) are both very low, so it is advantageous from the standpoint of pollution prevention. EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

However, the examples are merely for explanation and do not mean a limitation on the technical scope. Example 1 As the main components of the test cleaning agent, several types of condensed ammonium phosphates with different degrees of condensation, primary ammonium phosphate, secondary ammonium phosphate, and ammonium pyrophosphate, and several types of cleaning aids were added. Cleaning agents shown in Table 1 were prepared with or without addition.

Using the metal cleaning agent shown in Table 1, a cleaning test was conducted on aluminum, copper, and iron radiators that had dirt attached to them using the test equipment shown in the attached drawings.

The cleaning effect is determined by the difference in flow pressure of the cleaning solution before and after cleaning (P1-
P2) was evaluated. The results are shown in Table 2. As shown in the above table, in polyammonium phosphates, medium condensed ammonium phosphates, and high condensed ammonium phosphates with a degree of condensation in the range of 3 to 150, as long as urea, biuret, or triuret is present as an adjuvant, aluminum , iron and copper, showing excellent results for all types of metals (a-b-c-g-1, 1, n-0-q).

On the other hand, when primary ammonium phosphate, ammonium pyrophosphate, and diammonium phosphate are used as main agents, the cleaning ability is low even if cleaning aids are added (
d-e-f). Note that when ammonium polyphosphate, medium condensed ammonium phosphate, or high condensed ammonium phosphate is used as the main agent, the cleaning ability is excellent even in the absence of a cleaning aid (h-j-m),
In these cases, the action may be too strong and corrode the metal, as shown in Example 2 (Table 3) below. As the concentration of the cleaning agent or the cleaning temperature decreases, the time required for cleaning will naturally increase, but the cleaning effect itself will remain almost the same.

Example 2 Each plate-shaped test piece of aluminum, brass, and iron was left standing and immersed in the metal cleaning solution of Example 1, and the corrosiveness of the metal cleaning agent was determined by visual observation of the decrease (or increase) in thickness and the metal surface. Corrosivity was evaluated.

The results are shown in Table 3 (in the table, the numbers (f) indicate the amount of thickness reduction due to corrosiveness, and the numbers (b) indicate the amount of thickness increase due to corrosiveness). As shown in Table 3 below, primary ammonium phosphate, ammonium pyrophosphate, and diammonium phosphate are highly corrosive, and are highly corrosive even when a cleaning aid is added (d-e-f).

Furthermore, even when ammonium polyphosphate, medium condensed ammonium phosphate, or high condensed ammonium phosphate is used as the main ingredient, if a cleaning aid is not present, the same strong corrosivity is exhibited (h-j.m).

[Brief explanation of the drawing]

The drawing is a schematic diagram of the test apparatus used in the experiment of Example 2 of the present invention. The meanings of the symbols in the diagram are as follows: 1: Test radiator, 2: Filter 1, 3: Warming tank, 4: Heater 1,
5: Stirring propeller, 6: Pump, (P)1, [F]2
: Pressure gauge.

Claims (1)

[Scope of Claims] 1. A water-soluble metal cleaning agent containing condensed ammonium phosphate as the main cleaning agent component and containing urea or its modified component as an auxiliary agent. 2. The metal cleaning agent according to claim 1, wherein the condensed ammonium phosphate has a degree of condensation of 3 to 150. 3. The metal cleaning agent according to claim 1, wherein the urea transformation component as an auxiliary agent is biuret or triuret. 4. The metal cleaning agent according to any one of claims 1 to 3, wherein the ratio of condensed ammonium phosphate to urea or its modified component is 2:1 to 10:1 by weight. 5. The metal according to any one of claims 1 to 4, wherein condensed ammonium phosphate and urea or a modified component thereof are dissolved in water at a concentration of 1 to 50% by weight in total. Washing soap. 6 The metal to be cleaned is iron, aluminum, copper, zinc, alloys thereof, etc., and the cleaning agent is at room temperature to 90℃.
The metal cleaning agent according to any one of claims 1 to 5, which is used for cleaning in a temperature range of .degree.