KR900004880B1 - Composition and method for acid cleaning of aluminum surfaces - Google Patents

Abstract

An aq. cleaning compsn. (I), for removing and detaching fine parts of aluminium, and for cleaning lubricating oils from aluminium surfaces, contains 1-10 g/l H23SO4, 0.005-0.1 g/l HF and anionic surfactant. The improvement is that the compsn. (I) contains 0.1-10 g/l of alkali metal-2-butoxyethoxyacetate (II), esp. sodium-2-butoxyethoxyacetate, in amt. of 0.2-0.8 g/l. The compsn. (I) has a pH value of 1.0-1.8. The compsn. (I) also contains 0.1-10 g/l of a less foaming non-ionic surfactant. The compsn. has a good stability and cleaning effect.

Description

Compositions and methods for acid cleaning of aluminum surfaces

The present invention relates to a water soluble wash composition for cleaning aluminum surfaces and to a method and a concentrate used in the formation of the wash composition.

Drawing and forming operations are used in the manufacture of containers made of aluminum or aluminum alloys (referred to as drawing and ironing). In this operation, lubricant and forming oil remain on the surface of the aluminum container. In addition, the fine powder of residual aluminum, that is, small particles of aluminum accumulate on the inner and outer surfaces. Typically, during the drawing and ironing steps, the outer surface is not worn by the die, such as the inner surface, so that a small amount of aluminum fine powder remains on the outer surface of the container rather than the inner surface.

Prior to processing steps such as conversion coating or lacquer deposition, the surface of the aluminum container must be clean and free of water-bleak. That is, there should be no contaminants that impede further handling and make the container unsuitable for end use.

Compositions and methods for cold cleaning aluminum surfaces are described in US Pat. Nos. 4,009,115 (Robert Eric Beans, 1977.2.22), 4,116,853 (Robert Eric Beans, 1978.9.26), 4,124,407 (Robert Eric Beans, 1978.11.17). ) And 3,969,135 (Peter F. King, July 3, 1976). These patents address cleaning compositions containing sulfuric acid, hydrofluoric acid or fluoride salts and surfactants.

The compositions disclosed in these patents are currently commercially available and are actually used extensively for cleaning containers made of aluminum and aluminum alloys. These commercial compositions typically use a combination of two nonionic surfactants to improve cleaning performance and minimize foaming.

One of the problems with using conventional acid wash compositions is that as the aluminum container is treated with the cleaning solution, the accumulation of lubricants and forming oils used for drawing and forming the aluminum container is caused. Therefore, the cleaning solution must be changed from time to time to lower the oil level. If the oil level becomes excessive in the wash bath, the containers washed in the wash bath show significant water break after flushing out the wash liquid. A water brake means that the surface of the aluminum is not clean and oil or other foreign objects are present. Such cans or containers would be unsuitable for post-treatment as containers for storing beverages or other foodstuffs and would have to be discarded or washed again.

In the present invention, when certain anionic surfactants, such as alkali metal 2-butoxyethoxyacetates, are used alone or in combination with one or more low-foam nonionic surfactants in sulfuric acid / hydrofluoric acid compositions of the prior art, It can be seen that it brings surprising advantages over known compositions containing commonly used surfactants and surfactant complexes.

The washing solution of the present invention can withstand relatively high concentrations of lubricants or molding oils without generating any water breaks on the vessels washed with the solution. Therefore, it is possible to treat a large amount of containers without stopping the work to replenish all or part of the cleaning solution has a considerable economic advantage.

Another advantage of the present invention is that the composition of the present invention generates almost no bubbles in the washing tank and in the rinsing step following the washing step. A large number of acid wash compositions in circulation have a problem in that bubbles are generated although they differ in degree. Such compositions are mixtures of a highly foaming surfactant for good cleaning action with a low foaming anionic surfactant to contain a large amount of bubbles that would otherwise remain. The bubbles generated can overflow into work tools or fall to the floor, making them slippery or unstable. In addition, due to the generation of bubbles, the worker considers the cleaning solution unsatisfactory because of the risk of bubble overflow. Therefore, the container washing operation is stopped while removing the bubbles or replenishing the washing solution, which is time consuming and prevents the batch processing of a large quantity of containers.

Another advantage of the cleaning composition of the present invention is that it is effective even when using a relatively small amount of alkali metal 2-butoxyethoxyacetate, and is currently used because it is combined with a cheaper surfactant (sodium salt) compared to a conventional nonionic surfactant. It is a significant cost reduction effect than the composition that is. This cost savings effect is also achieved because non-ionic surfactants are present in relatively small amounts even if a low foaming nonionic surfactant or a combination of such surfactants is present in the wash compositions of the present invention.

Typically, concentrates containing sulfuric acid and surfactants are prepared by the producer and the container handling company purchases them, dilutes them with water and adds hydrofluoric acid to form a wash solution. Commercially available concentrates tend to be colored due to degradation products due to the action of concentrated conversion on the surfactant and degradation products due to surfactant interactions with impurities of commercial sulfuric acid. However, concentrates formed using alkali metal 2-butoxyethoxyacetate as surfactants were surprisingly colorless and sometimes weak yellow in color. These concentrates are stable at very low temperatures and do not precipitate at dry ice acetone baths. In addition, the concentrate is stable even under the conditions of 50 ° C. for a period of three weeks or longer, and does not discolor. However, most concentrates currently in use are decolorized even at room temperature, and depositing them in dry ice acetone baths can cause sedimentation. As described above, the composition of the present invention is excellent in stability and can be stored and transported at any temperature without any problem, so the economical advantages may be greater.

Another advantage of the present invention is the high degree of cleaning in the container. In particular, the presence of a low foaming nonionic surfactant provides uniform conversion coating and lacquer deposition on the vessel during post-treatment.

A small amount of the only anionic surfactants disclosed in US Pat. Nos. 4,009,115, 4,116,853 and 4,124,407 of Vienna, ie tergitol anionic 08 (sodium-2 ethylhexyl sulfate), was tested in the acid wash compositions of these patents. The water break appeared on the aluminum container washed with such a composition after addition of the molding oil. Thus, the surprising advantages found from the anionic surfactants of the present invention are unique and obviously not the advantages common to other conventional anionic surfactants.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The compositions and methods of the present invention include those that disclose the only compositions and methods disclosed in US Pat. Nos. 4,009,115, 4,116,853 and 4,124,407 to Vienna, which are incorporated herein by reference. In addition, the compositions and methods used in these references are equally applicable to the present invention unless otherwise stated.

]로서, 미라놀 화학회사에 의해 49.0% 나트륨 2-부톡시에톡시아세테이트를 함유하는 수용액으로서 "MIRAWET B"라는 상표명으로 시판되고 있다. 그러나 칼륨 2-부톡시에톡시아세테이트나 리튬 2-부톡시에톡시아세테이트와 같은 다른 알칼리금속 염들도 동등하게 사용될 수 있다. 선택적이기는 하나 통상, 0.1-10g/l, 바람직하게는 0.2-0.8g/l의 저기포성 비이온 계면활성제가 하나 또는 그 이상 존재하게 된다. 효과적으로는, 알칼리금속 2-부톡시에톡시아세테이트 대 비이온성 계면활성제의 무게비가 1:1인 것을 사용하는 것이다.The water-soluble washing composition of the present invention is 1-10 g / l, preferably 3-52 / l sulfuric acid; Hydrofluoric acid at 0.005-0.19 / l, preferably 0.01-0.03 g / l; And 0.1-10 g / l, preferably 0.2-0.8 g / l, consists of alkali metal-2 butoxyethoxyacetate. The alkali metal 2-butoxyethoxyacetate is preferably sodium 2-butoxyethoxyacetate [

] Is marketed under the trade name "MIRAWET B" by Miraol Chemical Company as an aqueous solution containing 49.0% sodium 2-butoxyethoxyacetate. However, other alkali metal salts such as potassium 2-butoxyethoxyacetate or lithium 2-butoxyethoxyacetate may equally be used. Although optionally optional, usually one or more of the low-foaming nonionic surfactants of 0.1-10 g / l, preferably 0.2-0.8 g / l are present. Effectively, the weight ratio of alkali metal 2-butoxyethoxyacetate to nonionic surfactant is 1: 1.

As used herein, the term "low foaming nonionic surfactant" means that a nonionic surfactant or a compound thereof generates bubbles of 20 mm or less after 5 minutes have elapsed in a known Ross-Mills bubble test at 50 ° C. Examples of such low-foaming non-dione surfactants that may be used alone or in combination in the practice of the present invention include the following; TRITON DF-16 (Rom and Haas Co.): A nonionic interfacial agent which is considered a modified polyethoxylated linear alcohol.

POLYTERGENT S-505 LF (Olin): A nonionic surfactant believed to be a modified polyethoxylated linear alcohol.

SURFONIC LF-17 (Jefferson Chemical Company): Nonionic surfactant believed to be an alkyl polyethoxylated ether.

ANTAOX BL 330 (Gap): Nonionic surfactants considered as alkyl poly (ethylene oxy) ethanol.

TRITON CF-10 (Rom and Haas): A nonionic surfactant believed to be an alkyl aryl polyether having a carbon chain of 14 carbon atoms and about 16 moles of ethoxylation.

PLURONIC LO 61 (BASF WIANTOT): Nonionic surfactants considered to be condensates containing only ethylene oxide and propylene oxide chains.

ANTAROX LF-330 (Gaf): A nonionic surfactant believed to be an alkyl poly (ethyleneoxy) ethanol.

MIN-FOAM 1 X (Union Carbide): A nonionic surfactant believed to be alkyloxy (polyethyleneoxypropyleneoxyisopropanol) having a molecular weight of about 706.

The pH of the washing compositions of the present invention is preferably maintained in the range of 1.0-1.8, most preferably 1.2-1.5, but it is also possible to use 0.6-2.0 pH.

Concentrates of the present invention which may be usefully used in forming the washing solution of the present invention are 200-600 g / l sulfuric acid and 0.01-10, preferably 0.04-0.27 alkali metal 2 per sulfuric acid in weight ratio. -Butoxyethoxyacetate. The ratio to alkali metal 2-butoxyethoxyacetate is an index, and the actual amount of alkali metal 2-butoxyethoxyacetate in the concentrate is within this ratio depending on the amount of sulfuric acid required in the washing solution of the present invention. When the concentrate is diluted with an appropriate amount of water, the required amount of alkali metal 2-butoxyethoxyacetate is present in the wash solution. For example, if 1 g / l sulfuric acid is required for the cleaning solution, 0.1-10 g of alkali metal 2-butoxyethoxyacetate per 1 g of sulfuric acid is present in the concentrate, and if 10 g / l sulfuric acid is required for the cleaning solution. 0.1-lg of alkali metal 2-butoxyethoxyacetate is present in the concentrate per gram of sulfuric acid.

The concentrate of the invention may also have a low foaming nonionic surfactant of 0.01-10, preferably 0.04-0.27, by weight.

The concentrate is added with an amount of water sufficient to make a wash solution having the required amount of sulfuric acid and alkali metal 2-butoxyethoxyacetate. An appropriate amount of hydrofluoric acid is added separately to the wash solution. When water is added to the concentrate, an amount of hydrofluoric acid may be added to the concentrate sufficient to make the required amount in the wash solution, but measured on a continuously controlled basis. More preferably, hydrofluoric acid is added to the washing solution in an amount. It is more preferable to monitor and add hydrofluoric acid separately because the cleaning solution continues to lose hydrofluoric acid upon etching of the aluminum vessel during the cleaning step.

The method of the present invention consists in contacting the water-soluble cleaning composition of the present invention with an aluminum or aluminum alloy surface to be cleaned using a known contacting technique such as a conventional spraying or locking method. The temperature of the cleaning composition is usually maintained in the range of 115 to 145 ° F (about 46 ° C. to about 63 ° C.) to obtain the maximum cleaning effect, but can be used at a temperature as low as 90 ° F (about 32 ° C.). . The treatment time with the washing solution is about 15 seconds-2 minutes. The hydrofluoric acid content of the wash solution and the contact time with the aluminum surface are adjusted to dissolve 8-25 mg, preferably 9-20 mg, per 1 ft ^{2 of} the aluminum surface to be treated.

The following examples are intended to illustrate the invention but not to limit it.

Example 1

Prepare 1 l of concentrate containing the following amounts of ingredients.

The concentrate was colorless and transparent. 5.940 l of water was added to 60.0 ml of the concentrate to contain 4.67 g / l of H ₂ SO ₄ (66 ° BOME) and 0.434 g / l of sodium 2-butoxyethoxyacetate (0.886 g / l MIRAWET B). Make 6 liters of solution. 20 ppm hydrofluoric acid is added to form a washing solution and stirred to make the composition uniform.

An aluminum can of 3004 alloy in a one piece container was used in this example. The can is covered with aluminum fine powder and drawing oil.

Process the specimen as follows.

(a) maintained for 1 minute with the washing solution maintained at 130 ° F (about 54 ° C.), (b) soaked in cold water for 30 seconds, rinsed, and (c) left for 30 seconds to investigate whether water breaks inside and outside the can. (D) wipe the inside with a clean white cloth and examine the finely divided aluminum fine powder.

Record the test results, add 5 ml of Reynolds Aluminum Cooling Oil Emulsion used for drawing and forming aluminum cans to the wash solution, test the other cans, and record the results. In addition, 5 ml of cooling oil is added to the wash bath, the other cans are tested and the results recorded. Add 5 ml of cooling oil again and test the can after each addition until a water break appears. Record the amount of bubbles in the wash bath with each addition of cooling oil.

The results of this test are shown in Table 1 below.

TABLE 1

Example 2

6 l washing solution is prepared by adding 28.02 g H ₂ SO ₄ (66 ° BOME), 27.84 g sodium 2-butoxyethoxyacetate and 20 ppm hydrofluoric acid to water. This wash solution contains 4.67 g / l H ₂ SO ₄ (66 ° BOME) and 0.217 g / l sodium 2-butoxyethoxyacetate (ie 1/2 of the amount present in the wash solution of Example 1). It is contained.

Aluminum cans were tested according to the same conditions and procedures as used in Example 1 to obtain the following results.

TABLE 2

Example 3

6 l of an aqueous washing solution containing the amount of the following composition per 1 l are prepared.

Aluminum cans were tested according to the same conditions and procedures as used in Example 1 to obtain the following results.

TABLE 3

Example 4

Except for setting the amount of sodium 2-ethylhexyl sulfate to 0.928g / l as in Example 3 to prepare a 6l aqueous washing solution. Table 4 shows the results of the test as in Example 3.

TABLE 4

Example 5

6 l of an aqueous washing solution containing the amount of the following composition per 1 l are prepared.

Aluminum cans were tested according to the same conditions and procedures as used in Example 1 to obtain the following results.

TABLE 5

Example 6

6 l of an aqueous washing solution containing the amount of the following composition per 1 l are prepared.

Aluminum cans were tested according to the same conditions and procedures as used in Example 1 to obtain the following results.

TABLE 6

Example 7

Prepare concentrates as follows.

Concentrate A was kept in an oven at 50 ° C. for 3 weeks. When it was taken out the solution was colorless and transparent. That is, no color change occurred during this period.

Example 8

6 l of an aqueous washing solution containing the amount of the following composition per 1 l are prepared.

TABLE 7

Example 8

This embodiment also uses an aluminum candle of 3004 alloy in a one-piece container. The cans are covered with aluminum fine powder and drawing oil.

Treat the specimens as follows.

(a) sprayed with the wash solution maintained at 125 ° F. (about 52 ° C.), (b) soaked in cold water for 30 seconds, rinsed off, and (c) left for 30 seconds to investigate the degree of water brake inside and outside. do.

The test results of the cans with a spraying time of 30 seconds in step (a) were recorded. The other can recorded the result with a spray time of 45 seconds. Next, 200 ppm of NALCO XL 174 (mineral oil from drawing lubricant and coolant) and a molded aluminum can are placed in the washing solution, and the third can is sprayed in step (a) for 30 seconds. The cans were tested with a spray time of 45 seconds in step (a).

The results of these tests are shown in Table 8.

TABLE 8

Example 9

4.7 g / l H ₂ SO ₄ (66 ° Baume), 1.053 g / l Hercules surfactant AR-150, 0.673 g / l Suponic LF 17, and 20 ppm hydrofluoric acid were added to the water, Manufacture.

The aluminum cans were tested in the same washing bath used in Example 8 according to the same conditions and procedures as in Example 8 to obtain the following results.

TABLE 9

Example 10

Prepare 6 l of wash solution severely contaminated with nalco XL 174, containing the amount of the following ingredients per 1 l.

This embodiment also uses an aluminum candle of 3004 alloy in a one-piece container. The cans are covered with aluminum fine powder and drawing oil.

Treat the specimens as follows.

(a) washed with water at 125 ° F. (about 52 ° C.) for 30 seconds, (b) sprayed with the wash solution at 125 ° F. (about 52 ° C.) for 40 seconds, and (c) spray-washed with water for 20 seconds. , (d) spray-wash with deionized water, (e) stand for 30 seconds, and then examine the internal and external water brake.

Record the test results of the cans treated as above. Next, 0.9 g / l of the low-foaming anionic surfactant is added to a part of the washing solution, and another can is tested as above. This process is repeated by adding 0.9 g / l of another low-foaming anionic surfactant to the other parts of the wash solution. These results are shown in Table 10.

TABLE 10

As can be seen in this example, the presence of a small amount of low-bubble nonionic surfactant in addition to the alkali metal 2-butoxyethoxyacetate, washing the composition even if a significant amount of the currently used coolant is present in the composition of the present invention Increased ability

Claims (20)

The lubricating oil on the aluminum surface, consisting of 1-10 g / l sulfuric acid, 0.005-0.1 g / l hydrofluoric acid and 0.1-10 g / l alkali metal 2-butoxyethoxyacetate, is washed and the aluminum fine powders are dissolved Water soluble wash composition for removal. The water-soluble washing composition according to claim 1, wherein the alkali metal 2-butoxyethoxy is sodium 2-butoxydiethoxyacetate and is present in an amount of 0.2-0.8 g per 1 l of the washing composition. The water-soluble washing composition according to claim 1, wherein the pH is 1.0-1.8. The water-soluble washing composition according to claim 2, wherein sulfuric acid is present in an amount of 3-5 g / l, and hydrofluoric acid is present in an amount of 0.01-0.03 g / l. 5. The hydrofluoric acid of claim 1, 2, 3 or 4 in an amount such that the composition may have an aluminum dissolution rate of 8-25 mg per 1 ft ² of the aluminum surface treated for 1 minute at 130 ° F. (about 54 ° C.). A water soluble cleaning composition, characterized in that present. The water-soluble washing composition according to claim 1, 2, 3 or 4, wherein one or a mixture of at least two low-foaming nonionic surfactants is present in the composition in an amount of 0.1-10 g / l. The water-soluble washing composition according to claim 1, 2, 3 or 4, wherein one or a mixture of at least two low-foaming nonionic surfactants is present in the composition in an amount of 0.2-0.8 g / l. Soluble to wash and dissolve aluminum powder lubricating oil on aluminum surface, consisting of 200-600 g / l sulfuric acid and 0.01-10 alkali metal 2-butoxyethoxyacetate per sulfuric acid in weight ratio in concentrate Aqueous concentrates used to prepare wash compositions. The aqueous concentrate of claim 8 wherein the alkali metal 2-butoxyethoxyacetate is sodium 2-butoxyethoxyacetate and is present in the concentrate in an amount of 0.04-0.27 per sulfuric acid by weight. The water soluble concentrate according to claim 8 or 9, wherein one or a mixture of two or more low-foam nonionic surfactants, per weight of sulfuric acid, is present in the concentrate in an amount of 0.01-10. 10. The water soluble concentrate according to claim 8 or 9, wherein one or a mixture of two or more low foaming nonionic surfactants, per weight of sulfuric acid, is present in the concentrate in an amount of 0.04-0.27. A method for cleaning an aluminum surface, the method comprising: (a) replacing the aluminum surface with 1-10 g / l sulfuric acid, 0.005-0.1 g / l hydrofluoric acid and 0.1-10 g / l alkali metal 2-butoxyethoxyacetate Contacting with a water-soluble washing solution, and (b) washing the aluminum surface to remove the washing solution. The method according to claim 12, wherein the alkali metal 2-butoxyethoxyacetate is sodium 2-butoxyethoxyacetate and is present in an amount of 0.2-0.8 g / l of the washing solution. 13. The method of claim 12, wherein the cleaning solution is sprayed onto the aluminum surface to contact the aqueous surface with the aqueous cleaning solution. The method of claim 12, wherein the temperature of the cleaning solution is maintained at 115 ° F.-145 ° F. (about 46 ° C.-about 63 ° C.). 13. The method according to claim 12, wherein the washing solution consists of 3-5 g / l sulfuric acid, 0.01-0.03 g / l hydrofluoric acid and 0.2-0.8 g / l sodium 2-butoxyethoxyacetate. . 17. The method of claim 12, 13, 14, 15 or 16, wherein 0.1-10 g / l of one or a mixture of at least two low-foaming nonionic surfactants is present in the aqueous wash composition. 17. The method of claim 12, 13, 14, 15 or 16, wherein 0.2-0.8 g / l of one or a mixture of at least two low-foaming nonionic surfactants is present in the aqueous wash composition. 18. The method of claim 17, wherein the aluminum surface is an aluminum can. 19. The method of claim 18, wherein the aluminum surface is an aluminum can.