JPH09111483A - Degreasing washing fluid and method for degreasing washing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a degreasing and cleaning soln. having the performance equivalent to a chloride-base solvent, usable instead of the chloride-base solvent and without toxicity and an effect on the environment.

SOLUTION: This degreasing and cleaning soln. consists of an aq. soln. contg. 10-40wt.% hydrogen peroxide and an appropriate amt. of at least one kind of stable wet surfactant among oxidizing agents. The soln. is suitable for the cleaning of an article, especially a metallic material. Although various surfactants can be used, the hydrophilic nonionic wet surfactants, especially ethoxysorbitan esters, are appropriately used. The weight ratio of the surfactant to hydrogen peroxide is preferably controlled to 1:3 to 1:100. Besides, the treating temp. is appropriately adjusted to 25-90°C and the treating time to 5-30min.

COPYRIGHT: (C)1997,JPO

Description

Detailed Description of the Invention

[0001]

The present invention relates generally to the field of industrial degreasing and cleaning of industrial products, the subject of which is mainly the use of hydrogen peroxide-based mixtures as cleaning degreasing liquids, in particular It relates to the use as a cleaning degreasing liquid for metallic materials.

[0002]

2. Description of the Related Art Mechanical parts are subjected to various cleaning and degreasing treatments during the manufacturing process. These degreasing treatments include a method using an aqueous solution and a method using a solvent.

Among the latter methods, petroleum-based solvents and chlorinated solvents have been widely used in recent years. Chloride-based solvent,
Chlorinated solvents and chlorofluorinated solvents
s) are divided into two subgroups. Chloride-based solvents are primarily used to clean and degrease metals at various stages. For example, degreasing between steps, final cleaning, degreasing before surface treatment, cleaning for maintenance, and the like.

These solvents, in fact, have many excellent properties for these applications. In particular, these solvents have excellent degreasing performance. That is, it is compatible with all the objects to be cleaned regardless of the type of contaminants removed by cleaning. In addition to these, the boiling points of these solvents are so low that they can be used in the gas phase with relatively low energy consumption. Furthermore, since these solvents do not have a flash point, they can be practically used without danger even at high temperatures.

However, chloride solvents are toxic to humans and are considered to be the cause of ozone layer destruction, and are harmful to the environment. For these reasons, chloride solvents are currently subject to strict regulations and their use is restricted. In particular, the use of chlorofluorocarbon solvents (CFC) and 1,1,1-trichloroethane (T111) is prohibited.

[0006]

[Problems to be Solved by the Invention] From the above background,
The object of the present invention is to solve the above technical problems.
It is an object of the present invention to provide a composition of a degreasing cleaning liquid which has a performance equivalent to that of a chloride-based solvent and can be used as a substitute for the chloride-based solvent without the disadvantages described above.

Another object of the present invention is to provide a method of using these degreasing cleaning liquids under industrial conditions in order to solve the above technical problems.

[0008]

[Means for Solving the Problems] 3 wt% to 50 wt%
Aqueous hydrogen peroxide and an aqueous solution containing an appropriate amount of at least one kind of wetting surfactant that is stable in an oxidizing agent have excellent degreasing performance, and are particularly useful as a degreasing cleaning liquid for metallic materials. It turned out to be possible. And this forms the basis of the invention.

Some of the mixed liquids used in the degreasing and cleaning method of the present invention are, in a comprehensive form, EP-035.
No. 1772.

More specifically, in this prior document,
An aqueous hydrogen peroxide solution containing any of the surfactants is described in a general form, and the weight ratio of the surfactant to hydrogen peroxide is approximately 1: 1 to 1: 1.
Up to 10,000. However, it should be noted that according to this prior art document, one of the essential functions of the surfactant is that the aqueous hydrogen peroxide solution is used for the catalytic action of metal ions, especially cupric ions. The other is to facilitate rinsing of the metallic material treated with an aqueous hydrogen peroxide solution. However, in EP-0351772, the person skilled in the art generally uses surface-active agents,
In particular, wetting surface-active age
nt) is not included as a reliable motivation to use to make a degreasing cleaning solution based on hydrogen peroxide.

(Invention of Claims 1 to 6) According to the first aspect of the present invention, the degreasing cleaning liquid of the present invention is used for degreasing cleaning of articles, particularly metallic materials. To 50 wt%, preferably 10 to 40 wt% hydrogen peroxide and an appropriate amount of at least one wetting surfactant stable in the oxidizing agent.

In the degreasing cleaning liquid of the present invention, many wetting surfactants can be used in order to improve the degreasing performance of the hydrogen peroxide aqueous solution. That is, anionic, nonionic, cationic, or amphoteric surfactants can be used as the surfactant.

Among the anionic surfactants,
The following can be used: monoesters of phosphoric acid, diesters of phosphoric acid.
), Organic phosphate triesters (triesters of phos
phoric acid), fatty acids and sulfonates (fat
ty acids and sulphonated esters), carboxylated ethoxylated f
atty alcohols) (Product name: Akypo, Chemy company
Manufactured) and alkylnaphthalene sulfonic acids (alkyln
aphtalenesulphonates).

Among the nonionic surfactants, in particular,
The following can be used: -The following nonalkoxylated derivatives: alkylpolyglucosides, fatty acid alkanolamides and amine oxides.
lkanolamides and amine oxides),-The following alkoxy derivatives (nonalkoxylated derivat)
ives): Alkoxy alcohols and alkylphenols, ethylene and propylene oxide copolymers
f ethylene and propylene oxides, ethoxylated fatty acids, ethoxylated sorbitan esters, ethoxylated glycerides, alkoxyamines and amides
), And alkoxy derivatives of perfluoro and polyfluoro alcohols.
fluorinated and polyfluorinated alcohols).

Among the cationic surfactants, particularly,
The following can be used: quaternary ammoniums and amine and imidazoline salts.

Finally, among the amphoteric surfactants, betaines can be used in particular.

Of the above, the best results have been obtained with the use of hydrophilic nonionic wetting surfactants, especially ethoxylated sorbitan esters.

The amount of the surfactant added depends, of course, on the nature of the surfactant and the general conditions under which the degreasing treatment is carried out.
However, it can be easily determined by those skilled in the art. Generally, the weight ratio of surfactant to hydrogen peroxide in the mixture used is between 1:10 and 1: 1,000, more preferably
It is between 1:30 and 1: 100. The aqueous hydrogen peroxide solution is prepared by diluting concentrated hydrogen peroxide with water.

In the present invention, when ethoxysorbitan esters are used under the conditions of a temperature of 60 ° C. and a hydrogen peroxide concentration of 35 wt%, the weight ratio of ethoxysorbitan esters to hydrogen peroxide is about 1: 100. Is preferred. When used at a temperature of 70 °, a solution containing 10 wt% to 15 wt% hydrogen peroxide as an activator and 0.3 wt% to 0.5 wt% ethoxysorbitan esters is preferable.

Among the ethoxysorbitan esters used in the present invention, particularly, ethoxylated sorbitan monolaurate (trade name: Mo).
ntanox 20, manufactured by Seppic company) is preferable.

(Invention of Claim 7) According to the second aspect of the present invention, the aqueous solution of the present invention contains 10 wt% as an activator.
To 15 wt% hydrogen peroxide and 0.3 wt% to 0.5 wt% ethoxysorbitan monolorate.

(Invention of Claim 8) According to the third aspect of the present invention, the aqueous solution of the present invention is used as an activator in an amount of 30
Hydrogen peroxide of 0.5 wt% to 50 wt% and 0.5 wt
% To 1.0 wt% ethoxysorbitan monolorate.

Such prepared aqueous solution should be diluted twice before use, or as a replenisher for re-adjusting the concentration of the aqueous hydrogen peroxide solution during the degreasing and cleaning operation. Used without.

In order to extend the life of the degreasing cleaning liquid, one or more additives having the function of stabilizing hydrogen peroxide may be added to the mixed liquid of the present invention. In particular, as a compound used for this purpose, a compound having a property of forming a complex with a metal is suitable. For example, aminocarboxylic and aminophosphonic compounds
), Or sodium stannate,
And stabilizers such as sodium pyrophosphate. Note that these are described in the above-mentioned prior documents.

(Invention of Claims 9 to 13) According to the fourth aspect of the present invention, the process of degreasing and cleaning an article, particularly a metallic material, of the present invention comprises:
In a treatment tank containing a mixed solution of hydrogen peroxide of t% or less and an appropriate amount of an aqueous solution containing at least one wettable surfactant stable in an oxidant, 15 ° C or more, 100 ° C or more.
℃ or less, preferably 25 ℃ or more, 90 ℃ or less, 5 seconds or more, 60 minutes or less, preferably 5 minutes or more, 3
It is characterized by comprising a step of immersing for a time of 0 minutes or less and a step of rinsing the article after the above treatment.

The properties of the surfactant and the concentrations of hydrogen peroxide and the surfactant in the degreasing cleaning liquid are the same as those defined above.

When the article is immersed in the processing tank,
It is even more effective if it is combined with a mechanical operation for promoting the contact between the article and the degreasing cleaning liquid. Such mechanical operations include, for example, jet jet, stirring means in the treatment tank or the article, or use of ultrasonic waves.

The temperature and the treatment time depend inter alia on the concentrations of hydrogen peroxide and surfactant. Generally, the higher the temperature, the shorter the processing time. Those skilled in the art
Appropriate temperatures and treatment times can be easily determined in each individual case.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION In order to investigate the degreasing performance of a mixed solution containing hydrogen peroxide and a surfactant, evaluation was carried out by the following method. The results are shown below.

Dirt was adhered to the surface of a stainless steel panel-shaped specimen (size: 10 cm × 10 cm) by a predetermined method. That is, for this purpose, the specimen was placed on the tray, the tray was rotated, and a mixture of oil in hexane was sprayed onto the surface of the specimen. The mixture of oil spreads on the surface of the specimen due to the centrifugal force generated by the rotation of the specimen. The amount of oil sprayed was such that the surface of the test piece was completely covered and excess oil was scattered from the edges. Oil was applied to both surfaces of each of the specimens. When the weight of the sample before and after the adhesion of oil stains was measured, the amount of oil adhered to each surface by this method was roughly on the order of 2 mg. This value corresponds to 0.2 g / m ² per unit area.

After the dirt was thus attached, the specimen was immersed in a beaker large enough to allow the panel specimen to be placed horizontally therein. A clean, hydrogen peroxide-inert support was sandwiched between the beaker bottom and the specimen so that the solution under test could circulate freely over the entire surface of the specimen.

The test at high temperature was carried out in a steam hood in an exhaust hood. The treatment tank was heated at a predetermined temperature until a thermal equilibrium state was reached, and then a panel-shaped specimen was immersed therein. Since the heat capacity of the sample is sufficiently small,
The temperature of the treatment tank does not change even when immersed in the treatment tank.

At the end of each test, the treated specimen was taken out of the treatment tank, rinsed with running water, and then dried in an upright position.

Evaluation of cleanliness is a difficult problem. In fact, there is currently no known simple, rigorous, and absolute way to quantify the cleanliness of the surface of an article.

One method that can be employed to assess the cleanliness of the surface of an article is the adhesive tape method.
This is a method called st). This method is performed as follows. That is, an adhesive tape of a certain length is carefully adhered to the surface of the specimen, then the adhesive tape is peeled off, and the adhesive tape is pasted on a blank paper. In this test method, it is assumed that the adhesive tape will carry away all the stains on the surface of the specimen panel where it was attached. Based on this premise, an adhesive tape is attached on a white paper, and the change in color is compared with a scale prepared in advance to visually evaluate the state of stains. However, this method does not cause any change in the color of the adhesive tape when the oil adhering to the surface of the stainless steel specimen is colorless,
Not applicable.

The method adopted in confirming the effect of the cleaning process according to the present invention is another method using an adhesive tape. This method is based on the finding that the color of clean specimens is lighter than the color of soiled specimens. Assuming that the adhesive tape will carry away all dirt from the surface of the test piece due to oil, when the adhesive tape attached to the surface of the dirty test piece is peeled off, a trace is left on the surface of the test piece. Therefore, the state of degreasing in the treatment tank can be evaluated by comparing the traces left on the surface of the specimen in this way.

For this purpose, the traces of the adhesive tape left on the surface of the panel-shaped specimen are as follows.
A five-level evaluation scale was created.

Level 0: No change, that is, the specimen panel retains its original color. In this case, it is obvious that a large amount of oil adheres to the surface when touched.

Level 1: A recognizable slight change in color is recognized. However, a considerable amount of oil is attached to the surface so that you can see it when you touch it.

Level 2: Adhesion of oil cannot be perceived just by touching the surface, but traces of the adhesive tape can be visually discerned, and edges of traces are continuous.

Level 3: Traces of the adhesive tape are difficult to discriminate visually.

Level 3: No trace of the adhesive tape can be visually discerned.

Preliminary tests have revealed that the rinse plays a significant role in the degreasing process according to the invention.

In fact, upon removal from the processing bath, the specimen is covered with a film of liquid containing hydrogen peroxide, surfactants and various substances due to dirt. The last of these, generally oily and hydrophobic, forms micelles with molecules of surfactant. After evaporation of water and hydrogen peroxide by drying,
These micelles redeposit on the surface of the specimen. Therefore,
In order to obtain the desired effect, it is particularly important to rinse the specimen immersed in the treatment tank.

[0045]

EXAMPLES Table 1 shows the results of various tests performed to investigate the cleaning performance of hydrogen peroxide and surfactant-based mixtures.

[0046]

[Table 1] The wetting surfactant used in these tests was ethoxylated sorbitan.
monolaurate; trade name Monotanox 20; above).

It should be noted that this surfactant is merely an example of a concrete and preferable surfactant. Also, as pointed out above, the person skilled in the art will be able to find other compounds which bring about the required results, in particular among the types of surfactants mentioned above.

Test No. 1 was carried out under relatively severe processing conditions. The concentration of hydrogen peroxide is 35 wt%, the treatment temperature is 70 ° C., and the immersion time is 30 minutes. Under this condition, a particularly remarkable degreasing performance was recognized. In fact, in the above test, the surface of the specimen was clean after rinsing and drying.

The following four tests (tests No. 2 to No. 5) were carried out in order to examine the role of each component of the treatment tank. In these tests, the temperature of the treatment bath was 70 ° C to 75 ° C and the immersion time was 15 minutes.

In the case of a treatment tank consisting of distilled water only (Test N
o.3), no effect was observed.

When only the aqueous hydrogen peroxide solution was used (Test No. 4), only mediocre results were obtained.

Similarly, when only the surfactant was used (Test No. 5), only mediocre results were obtained.

On the other hand, the combination of hydrogen peroxide and a surfactant proved to be very effective (test No. 2).

Subsequent tests (No. 6, No. 7, No. 6)
8) was carried out in order to investigate the role of the temperature of the processing tank. According to the test results, the temperature is an important factor for obtaining the desired result, and it was found that there is a threshold value below which the effect is not observed when the treatment time is constant.

In these tests, when a surfactant was used, this threshold was in the range between 50 ° C. and 70 ° C., with an immersion time of 15 minutes. In the range of temperatures and immersion times used in the mechanical industry, tests at 60 ° C. have been found to give relatively good results.

Subsequent tests (No. 9 to No. 14) were carried out in order to investigate the effect of immersion time on the state of degreasing. According to the test results, the immersion time is an important factor for obtaining the desired result, and it was found that there is a threshold value below which the effect is not observed when the temperature of the treatment tank is constant. .

From the results of the tests No. 9 to No. 12 carried out in the temperature range between 80 ° C. and 87 ° C., in order to obtain a satisfactory level of cleanliness, at least about 2.5 minutes, It was found that the soaking time was required.

Tests No. 13 and No. 14 show that good results are obtained when the temperature of the treatment bath is 90 ° C. and the immersion time is 2.5 minutes.

As described above, in the case of the cleaning process according to the present invention, the immersion time can be shortened whenever necessary. However, in that case, it is necessary to raise the temperature of the processing bath until the desired result is obtained.

Subsequent tests (No. 15 to No. 17) show that the immersion time and temperature can also be reduced simultaneously if a mechanical treatment such as the use of ultrasonic waves is used during immersion. Is possible. According to this method, good results can be obtained with an immersion time of the order of 1 minute and a temperature of the order of 70 ° C.

The following test (No. 18) shows that the concentration of the surfactant is an important factor for obtaining the required result, and that the immersion time and the treatment temperature are constant. It indicates that there is a threshold value below which the effect is not observed.

When ethoxysorbitan monolorate was used as the surfactant, the best concentration of the surfactant was 3.5 g / l under the industrially applicable processing conditions.

Tests No. 19 and No. 20 show that the concentration of hydrogen peroxide required to obtain the required results depends on the processing temperature.

Particularly, No. 20, if the processing temperature is 70 ° C.
It is possible to use an aqueous solution of hydrogen peroxide having a concentration of 15% if the temperature is increased to, and a result equivalent to level 3+ can be obtained by soaking for about 5 minutes,
Is shown.

In order to evaluate the stability of the solution, the hydrogen peroxide concentration and pH were measured periodically. As a result, the following was revealed. That is, the pH of the treatment tank was almost constant before and after cleaning, and the value was about 2.5. In contrast, the concentration of hydrogen peroxide increased slightly during the treatment. This is presumably because the concentration of hydrogen peroxide increased due to the evaporation of water. However, this phenomenon is almost negligible.

[0066]

The cleaning process according to the invention has many advantages.

Among them, the most important and noteworthy point is
This process can be easily carried out using existing equipment and is generally biodegradable.
The use of a surfactant provided with does not cause pollution in practical use.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Thierry Saint-Angele France, 94230 Cachan, Ryu de Rohan 33 (72) Inventor Christine Devos France, 78000 Versailles, Ryu Moliere 1 (72) Invention Lemon Soumarmont France, 93130 Noissy Le Secque, Batiman 3, Abnu Alsace Lorraine 17 (72) Inventor Eric Du Chateau United States, Illinois 60514, Clarendon Hills, Coe Lord 211

Claims (13)

[Claims] 1. 3 wt% or more and 50 wt% or less, preferably 10 wt% or more and 40 wt% or less hydrogen peroxide, and an appropriate amount of at least one wettable surfactant stable in an oxidizing agent. A degreasing cleaning liquid for articles, especially metallic materials, consisting of an aqueous solution containing. 2. The degreasing cleaning liquid according to claim 1, wherein the wetting surfactant is one or more compounds selected from the following group: Organic phosphoric acid monoesters (Organic monoesters of
phosphoric acid), organic diesters of phos
phoric acid), organic phosphate triesters (organic triesters of p
hosphoric acid), fatty acids and su
lphonated esters), carboxy-ethoxy fatty acid alcohols and alkylnaphthalene sulfonic acids
ty alcohols and alkylnaphtalenesulphonates), alkylpolyglucosides, fatty acid alkanolamides and amine oxides (fatty)
acid alkanolamides and amine oxides), alkoxy alcohols and alkylphenols (alko
xylated alcohols and alkylphenols), ethylene and propylene oxide copolymers (copolyme
rs of ethylene and propylene oxides), ethoxylated fatty acid, ethoxylated sorbitan
esters), ethoxylated glycerides, alkoxyamines and amides
and amides), and alkoxy derivatives of perfluoro and polyfluoroalcohols.
nd polyfluorinated alcohols), quaternary ammoniums, amine and imidazoline salts
salts and betaines) and betaines. 3. The degreasing cleaning liquid according to claim 1 or 2, wherein the wettable surfactant is one or more compounds selected from the following group: Nonionic surfactants, especially ethoxylated sorbitan ester
s). 4. The weight ratio of surfactant to hydrogen peroxide in the aqueous solution is in the range of 1:10 to 1: 1000, preferably 1:30 to 1: 100. The degreasing cleaning liquid according to any one of claims 1 to 3. 5. The degreasing cleaning liquid according to any one of claims 1 to 4, wherein the aqueous solution contains 35 wt% hydrogen peroxide. 6. The aqueous solution is 10 wt% or more and 15 w
t% or less of hydrogen peroxide, and 0.3 wt% or more of 0.
The degreasing cleaning liquid according to any one of claims 1 to 4, which contains 5% by weight or less of ethoxysorbitan esters. 7. As an activator, 10 wt% or more, 15 w
t% or less hydrogen peroxide, and 0.3 wt% or more, 0.5
% Wt or less ethoxysorbitan monolorate
Aqueous solution containing lated sorbitan monolaurate). 8. As an activator, 30 wt% or more, 50 w
Hydrogen peroxide of t% or less, and 0.5 wt% or more, 1% w
ethoxysorbitan monolorate (t or less)
An aqueous solution containing d sorbitan monolaurate). 9. Treatment of an article with a mixture comprising an aqueous solution containing 3 wt% or more and 50 wt% or less hydrogen peroxide and an appropriate amount of at least one wettable surfactant stable in an oxidizing agent. In the tank, 15 ℃ or more, 100 ℃ or less,
Preferably, a step of immersing at a temperature of 25 ° C. or higher and 90 ° C. or lower for 5 seconds or longer and 60 minutes or shorter, preferably 5 minutes or longer and 30 minutes or shorter, and rinsing the article after the treatment An article, particularly a method for degreasing and cleaning a metallic material, comprising: 10. A mechanical operation for facilitating contact between an article and a degreasing cleaning liquid when the article is immersed in a treatment bath,
The method of degreasing and cleaning according to claim 9, characterized in that the use of ultrasonic waves is used in combination. 11. The degreasing cleaning method according to claim 9 or 10, wherein the degreasing cleaning liquid according to claim 5 is used, and the treatment temperature is about 60 ° C. 12. The degreasing cleaning method according to claim 9 or 10, wherein the degreasing cleaning liquid according to claim 7 is used and the treatment temperature is about 70 ° C. 13. The degreasing cleaning liquid used is a solution obtained by diluting the aqueous solution according to claim 8 in half, and the processing temperature is about 70 ° C., wherein the treatment temperature is about 70 ° C. Degreasing and cleaning method.