JPH0352550B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aluminum surface cleaning composition and a cleaning method containing sulfuric acid, hydrofluoric acid, and an alkali metal salt of 2-butoxyethoxyacetic acid. Deep drawing and forming operations (commonly referred to as deep drawing and ironing) are used in the manufacture of containers made of aluminum and aluminum alloys. This operation causes lubricating oil and molding oil to adhere to the surface of the aluminum container. Furthermore, residual aluminum fine particles, ie, small aluminum particles, adhere to both the inside and outside surfaces. The outer surface of the container usually has less aluminum particulates than the inner surface because the outer surface is not as worn by the die as the inner surface during the deep drawing and ironing process. Conversion paint and sanitary paint
Before any manufacturing process, such as painting (lacquer), the surface of an aluminum container must be cleaned and freed of water, i.e. to remove dirt that would interfere with the subsequent process and render the container unusable. Compositions and methods for low temperature cleaning of aluminum surfaces are disclosed in U.S. Pat. No. 4,009,115 (February 22, 1977).
Robert Eric Binns), No. 4116853 (September 26, 1978, same), No. 4124407 (November 7, 1978, same), and No. 3969135 (July 13, 1976) published by Peter F. King, etc.). These patents disclose cleaning compositions containing sulfuric acid, hydrofluoric acid or fluoride salts, and surfactants. Compositions based on the disclosures of these patents have been industrialized and are in fact widely used in cleaning aluminum and aluminum alloy containers. Such commercially available compositions are typically used in combination with two nonionic surfactants to enhance detergency and suppress foaming. One of the problems with these known acid cleaning compositions is in the preparation of lubricating and forming oils used in deep drawing and forming of aluminum containers since the containers are treated with the cleaning fluid. The cleaning fluid must be replenished from time to time with fresh solution so that the oil level is kept low. When the level of oil becomes excessive in the wash bath, containers that have been washed in the bath exhibit significant water drainage after the wash liquid has been washed off. Water is an indication that the aluminum surface is not clean and has oil or other foreign matter on it. Such metal containers are undesirable for downstream processing of beverage and other food containers and must be discarded or recleaned. Herein, the present inventors describe a specific anionic surfactant,
That is, when an alkali metal salt of 2-butoxyethoxyacetic acid is used alone or in combination with one or more low-foaming nonionic surfactants in known sulfuric acid/hydrofluoric acid compositions, the previously used interface It has been found that the present invention has surprising advantages over known compositions containing combinations of active agents and surfactants. It has been found that the cleaning liquid of the present invention does not cause water generation at all in containers cleaned with the cleaning liquid, even in relatively high concentrations of lubricating oil and molding oil. This is therefore very economical, since a large number of containers can be processed before the operation has to be interrupted in order to replenish all or part of the cleaning liquid. Another major advantage of the cleaning compositions of the present invention is the complete elimination of foaming in the cleaning bath and in the rinsing process that follows the cleaning process. Many conventional commercially available acid cleaning compositions have the problem of producing a lot or a little foaming. Such a composition is
It is a mixture of a high foaming nonionic surfactant that achieves good cleaning action and a low foaming anionic surfactant that provides the foaming that would otherwise occur. Foaming often results in overflow or foam falling onto the floor of the facility where the equipment is located, leading to slippery and unstable conditions. Foam generation may also cause the operator to believe that the cleaning fluid is not sufficient for the risk of foam overflow. Therefore, the container cleaning process must be interrupted while skimming the foam or replenishing the cleaning solution, resulting in loss of time and reduced container throughput. Still other advantages of the cleaning composition of the present invention are 2-
The alkali metal salt of butoxyethoxyacetate can be used effectively in a relatively small amount and is also used together with the surfactant (when it is a sodium salt) which is already cheaper than the nonionic surfactants conventionally used. It is very economical compared to currently commercially available compositions. The relatively small amount of nonionic surfactants also makes the low foaming nonionic surfactants or combinations of surfactants considerably less expensive when present in the cleaning compositions of the present invention. Concentrates, usually containing sulfuric acid and surfactants, are produced by manufacturers and sold to container manufacturers.
A cleaning solution is made by diluting the concentrate with water and adding hydrofluoric acid thereto. Conventional commercially available concentrates are produced by decomposition products formed by the action of concentrated sulfuric acid on the surfactant and/or the interaction of the surfactant with impurities in the commercially available sulfuric acid typically used to form the concentrate. It tends to be quite pigmented. Surprisingly, the concentrate formed by the alkali metal salt of 2-butoxyethoxyacetic acid present as the sole surfactant is colorless or only slightly yellow. The concentrate is stable even at extremely low temperatures,
For example, no precipitation occurs even at the temperature of a dry ice-acetone bath. Furthermore, the concentrate is stable even at high temperatures and does not change color even after being stored at 50°C for 3 weeks or more. Most conventionally used concentrates change color even at room temperature, and significant precipitation occurs when the concentrate container is placed in a dry ice-acetone bath. The compositions of the present invention are very stable and can be transported and stored without problems even under adverse temperature conditions, and are also very economically advantageous. Other advantages of the present invention are that it produces a high degree of cleanliness of the container, especially when low foaming nonionic surfactants are present, and always provides a uniform conversion coating and lacquer coating of the downstream container. It's about doing. Interestingly, US patent no.
4009115, 4116853 and 4124407, i.e.
When Tergitol Anionic 08 (sodium 2-ethylhexyl sulfate) was tested in the acid cleaning compositions of these patents, water developed in aluminum containers cleaned with these compositions after addition of a small amount of molding oil. The surprising advantages found for the anionic surfactants of the present invention, which are clearly outstanding, are therefore not advantages commonly found in anionic surfactants. The present invention relates to aqueous cleaning compositions and methods for cleaning aluminum surfaces, as well as concentrates used to form the cleaning compositions. The compositions and methods of the present invention are particularly described in the related U.S. Pat.
It is an improvement over the compositions and methods disclosed and claimed in Nos. 4009115, 4116853, and 4124407. The means and methods for carrying out the washing operation and forming the concentrate and washing liquid described in that patent can be similarly used in the present invention, unless otherwise specified. The aqueous cleaning composition of the present invention comprises about 1 to 10 g of sulfuric acid/
, preferably about 3-5 g/hydrofluoric acid
0.005-0.1g/, preferably about 0.01-0.03g/
, and about 0.1 to 10 g/, preferably about 0.2 to 0.8 g/alkali metal salt of 2-butoxyethoxyacetic acid.
Consisting of The alkali metal salt of 2-butoxyethoxyacetic acid is sodium 2-butoxyethoxyacetate. is preferred, which is an aqueous solution containing 49.0% sodium 2-butoxyethoxyacetate and has the trade name "MIRAWET B" (mirranol chemical
Company, Inc.). Other alkali metal salts, such as potassium 2-butoxyethoxyacetate or lithium 2-butoxyethoxyacetate, can be used with preference as well. Furthermore, one or more low-foaming nonionic surfactants about 0.1 to 10 g/, preferably about 0.2 to 0.8
g/ may be present. The weight ratio of alkali metal salt of 2-butoxyethoxyacetic acid to nonionic surfactant is preferably about 1:1. The term "low foaming nonionic surfactant"
It means a nonionic surfactant, or a combination thereof, which produces a foam of 20 mm or less after standing for 5 minutes in the well-known Ross-Miles foaming test at °C. Examples of the low foaming nonionic surfactants that can be used alone or in combination in the practice of the present invention include the following. TRITON DF-16 (Rohm & Haas Co; nonionic surfactant presumed to be modified polyethoxylated linear alcohol) POLYTERGENT S-505 LF (Olion
Corp.; nonionic surfactant presumed to be modified polyethoxylated linear alcohol) SURFONIC LF-17 (Jefferson Chemical
Co.; nonionic surfactant presumed to be alkyl polyethoxylated ether) ANTAROX BL 330 (GAF Corp; nonionic surfactant presumed to be alkyl poly(ethyleneoxy) ethanol) TRITON CF-10 (Rohm & Haas Co. ; Nonionic surfactant, alkylaryl polyether having a carbon chain of about 14 carbon atoms, about 16 mol%
) PLURONIC LO61 (BASF Wyandotte,
Inc.; nonionic surfactant, presumed to be a condensate consisting only of ethylene oxide and propylene oxide) ANTAROX LF-330 (GAF Corp.; nonionic surfactant, presumed to be alkylpoly(ethyleneoxy)ethanol) MIN-FOAM 1X (Union Carbide Corp.; nonionic surfactant, estimated to be alkyloxy (polyethyleneoxypropyleneoxyisopropanol) having a molecular weight of about 706) The PH of the cleaning composition of the present invention is about 1.0 to 1.8. The pH is preferably maintained at about 1.2 to 1.5, but it can also be used at a pH of 0.6 to 2.0. The concentrates of the present invention can be advantageously used to form the cleaning solutions of the present invention and contain approximately 200 to 600 sulfuric acid.
The concentrate contains about 0.01 to 10 parts, preferably about 0.04 to 0.27 parts, of the alkali metal salt of 2-butoxyethoxyacetate per 1 part by weight (hereinafter simply referred to as parts) of sulfuric acid. Based on the required amount of sulfuric acid in the cleaning solution of the invention, using alkali metal 2-butoxyethoxyacetate based on the above ratio, the desired amount of 2-butoxyethoxyacetate is used when the concentrate is diluted with an appropriate amount of water. -2- in the concentrate such that an alkali metal salt of butoxyethoxyacetic acid is present in the washing solution.
The actual amount of alkali metal salt of butoxyethoxyacetic acid is determined within the above ratio. For example, if 1 g of sulfuric acid is required in the cleaning solution, approximately 1 g of 2-butoxyethoxyacetic acid alkali metal salt is added to the concentrated solution.
0.1-10g is present. In addition, 10% sulfuric acid is added to the cleaning solution.
If 1 g/g of sulfuric acid is required, approximately 1 g of 2-butoxyethoxyacetic acid alkali metal salt is added to the concentrate.
0.1-1 g is present. Furthermore, about 0.01 to 10 parts, preferably about 0.04 to 10 parts, of one or more low foaming nonionic surfactants.
0.27 parts may be present in the concentrate of the invention. The concentrate is then treated with a desired amount of sulfuric acid and 2-
A sufficient amount of water is added to produce a cleaning solution containing the alkali metal salt of butoxyethoxyacetic acid. The required amount of hydrofluoric acid is usually added separately to the cleaning solution. Hydrofluoric acid can be added to the concentrate in sufficient quantities to produce the required amount in the cleaning solution when the concentrate is added to water, but it is also possible to It is preferable to measure the amount and add it to the cleaning solution one by one. Since hydrofluoric acid is continuously lost from the cleaning solution when etching of the aluminum container occurs during the cleaning process, it is preferable to separately monitor and add hydrofluoric acid. The method of the invention also comprises contacting the aluminum or aluminum alloy surface to be cleaned with the aqueous cleaning composition of the invention using any known contacting technique, such as conventional spraying or dipping techniques. The temperature of the cleaning composition is preferably maintained at about 115 to 145 degrees for maximum cleaning effectiveness;
Can be used even at low temperatures below 90%. The treatment time with the cleaning solution is usually approximately 15 seconds to 2 minutes. Desirably, the hydrofluoric acid content of the cleaning solution and the contact time with the aluminum surface are adjusted to result in dissolution of about 8 to 25 mg, preferably about 9 to 20 mg of aluminum per square foot of treated aluminum surface. be done. Next, the present invention will be explained based on Examples, Comparative Examples, and Reference Examples, but these do not limit the present invention. Example 1 A concentrate 1 containing the following amounts of ingredients is prepared. H ₂ SO ₄ (66° Be ) 467.2 g (256 ml) H ₂ O 709.6 g (711 ml) MIRAWET B 88.6 g (80 ml) The concentrate is clear and virtually colorless. Add 60.0ml of the concentrate to 5.94ml of water and dilute with H ₂ SO ₄ (66°Be)
4.67g/and sodium 2-butoxyethoxyacetate (MIRAWET B 0.886g/) 0.434
Make solution 6 containing g/. hydrofluoric acid
20 ppm is added to form a wash solution and the wash solution is stirred to form a homogeneous composition. An aluminum can made of 3004 alloy that is deep drawn into a one-piece container is used in the method of the present invention. The can is covered with aluminum particles and deep drawing oil. The test specimens were treated as follows. (a) Spray the above cleaning solution maintained at 130〓 for 1 minute, (b) Soak in water for 30 seconds and wash with water, (c) Leave it to stand for 30 seconds, then check the water repellency on both the inside and outside, and then ( d) Wipe the inside surface with a clean cloth and examine the cloth for aluminum particles. Test the can as above and record the results.
Next, 5 ml of a cooled emulsion oil used by Reynolds Aluminum Company in deep drawing and forming aluminum cans is added to the cleaning solution, and other cans are tested and the results are recorded. Then add another 5 ml of cooling oil to the bath, test the other can and record the results. Test the can with 5 ml increments of cooling oil until water appears. Record the amount of foam in the bath with each increase in cooling oil. The results of these tests are shown in Table 1 below.

【table】

[Table] Example 2 28.02 g of H ₂ SO ₄ (66°Be), 1.30 g of sodium 2-butoxyethoxyacetate and hydrofluoric acid in water
20ppm was added to prepare the cleaning solution No. 6. This wash solution contains 4.67 g/H ₂ SO ₄ (66°Be) and 0.217 g/sodium 2-butoxyethoxyacetate (ie, 1/2 of the wash solution of Example 1 is present). The same batch of aluminum cans used in Example 1 was tested under the conditions and method of Example 1. The results are shown below.

[Table] Comparative Example 1 Aqueous cleaning liquid containing the following amounts of components per unit 6
I made it. H ₂ SO ₄ (66°Be) 4.67g Sodium 2-ethylhexyl sulfate
0.464g (TERGITOL ANIONIC 08 0.98ml) HF 20ppm The same batch of aluminum cans used in Example 1 was tested under the conditions and method of Example 1. The results are shown below.

[Table] * Comparative example that is not acceptable in practice 2 Sodium 2-ethylhexyl sulfate 0.928g/
An aqueous cleaning solution of No. 6 was prepared containing the same amounts of components as in Comparative Example 1, except that . The test method was the same as in Comparative Example 1, and the following results were obtained.

[Table] * Comparative Example 3 which is not acceptable in practice An aqueous cleaning composition 6 containing the following amounts of ingredients per unit was prepared. H ₂ SO ₄ (66°Be) 4.70g Ethoxylated Abietic Acid (Hercules Surfactant
AR 150) ^* 1.053g Alkylpoly(ethyleneoxy)ethanol (ANTAROX LF-330) ^* 0.673g HF 20ppm *Both are nonionic surfactants The same batch of aluminum cans used in Example 1 was used in the method of Example 1. The results of processing according to the following conditions are shown below.

[Table] * Practically unacceptable ** 1/4″~1″
Comparative Example 4 Aqueous cleaning liquid 6 containing the following amounts of components per unit:
I made it. H ₂ SO ₄ (66°Be) 4.67g Modified polyethoxylated linear alcohol (TRITON
DF-16, nonionic surfactant) 0.464g HF 20ppm The same batch of aluminum cans used in Example 1 was treated according to the method and conditions in Example 1. The results are shown below.

[Table] Reference Example 1 The following concentrated solution was prepared. A Per unit (g) H ₂ SO ₄ (66°Be) 467.2 H ₂ O 709.6 Sodium 2-butoxyethoxyacetate 43.4 B Per unit H ₂ SO ₄ (66°Be) 467.2 H ₂ O 709.6 Sodium 2-ethylhexyl sulfate 46.4 C H ₂ SO ₄ (66°Be) 469.6 H ₂ O 627.0 Ethoxylated abietic acid (Hercules
Surfactant AR 150) 67.3 D H ₂ SO ₄ (66°Be) 467.2 H ₂ O 709.6 Modified polyethoxylated linear alcohol (TRITON DF-16) 46.4 A sample of the above concentrate was treated under the above conditions, and the following 7th The results are shown in the table.

[Table] forms a layer on top of the sulfuric acid solution.
Concentrate A was then placed in a furnace maintained at 50°C for 3 weeks. When the solution was removed, it was clear and virtually colorless, ie, there was no discoloration during this period. Example 3 Six aqueous cleaning solutions were prepared containing the following amounts of ingredients per portion. H ₂ SO ₄ (66°Be) 4.7 g MIRAWET B 0.9 g HF 20 ppm Aluminum cans made of 3004 alloy deep drawn into a one-piece container are used in the method of the invention. The can is covered with aluminum particles and deep drawing oil. The test specimens were treated as follows. (a) Spray the above cleaning solution maintained at 125㎓, (b) rinse by immersing in cold water for 30 seconds, (c) leave to stand for 30 seconds, then check the water repellency on both the inside and outside. The first can is tested as above with a spray time of 30 seconds in step (a) and the results are recorded. A second can is tested as above with a 45 second spray time in step (a) and the results are recorded. Next, NAL CO
XL 174 (deep drawing cooling, mineral oil based lubricant) and an ironed aluminum can were added to the cleaning solution and a third can was tested as above with a spray time of 30 seconds in step (a) and then A fourth can is tested with a spray time of 45 seconds in step (a). The results of these tests are shown in Table 8 below.

[Table] Comparative example 5 H ₂ SO ₄ (66°Be) 4.7g/, Hercules
Surfactant AR−150 1.053g/, SURFONIC
Washing liquid 6 was prepared by adding 0.673 g of LF 17 and 20 ppm of hydrofluoric acid to water. The same batch of aluminum cans as in Example 3 was tested according to the conditions and method of Example 3, and the results are shown below.

[Table] Example 4 NALCO XL containing the following amounts of ingredients per unit
174, a highly contaminated aqueous cleaning solution 6 was prepared. H ₂ SO ₄ (66°Be) 4.7 g MIRAWET B 0.9 g HF 20 ppm NALCO XL 174 500 ppm An aluminum can of 3004 alloy deep drawn into an integral container is treated by the method of the present invention. The can is covered with aluminum particles and deep drawing oil. The test specimens were treated as follows. (a) Clean with tap water at 125〓 for 30 seconds, (b) Spray the above cleaning solution maintained at 125〓 for 40 seconds, (c) Spray tap water for 20 seconds and clean, (d) Deionize. Spray with water to clean. (e) Leave to stand for 30 seconds, then check for water generation on both the inside and outside. The cans were tested as described above and the results recorded. 0.9 g/low foaming nonionic surfactant is then added to a portion of the contaminated wash solution and the other cans are tested as above. The process is repeated with 0.9 g/d of a different low foaming nonionic surfactant added to a new contaminated cleaning solution. The results obtained are shown in Table 10 below.

[Table] As is clear from the above examples, even when the compositions of the present invention are heavily contaminated with commercially available coolants, the small amount added to the alkali metal salt of 2-butoxyethoxyacetic acid The presence of the low foaming nonionic surfactant greatly increases the detergency of the composition.

Claims (1)

[Claims] 1. Approximately 1 to 10 g of sulfuric acid/approximately 0.005 of hydrofluoric acid
An aqueous cleaning composition for removing and dissolving aluminum fine particles from aluminum surfaces and cleaning lubricating oil, characterized in that it contains ~0.1 g/ and about 0.1-10 g/ of an alkali metal salt of 2-butoxyethoxyacetic acid. 2. The alkali metal salt of 2-butoxyethoxyacetic acid is sodium 2-butoxyethoxyacetate,
The aqueous cleaning composition of paragraph 1 above, present in the cleaning composition from about 0.2 to 0.8 g/g/. 3. The aqueous cleaning composition of item 1 above, having a PH of about 1.0 to 1.8. 4 Approximately 3 to 5 g of sulfuric acid/and approximately hydrofluoric acid
The aqueous cleaning composition of item 2 above, wherein 0.01 to 0.03 g/g is present. 5. Hydrofluoric acid is present in an amount such that the composition has an aluminum dissolution rate of about 8 to 25 mg per square foot of treated aluminum surface at a temperature of 130°C and a contact time of 1 minute. Aqueous cleaning composition according to any one of the above. 6 One type or a mixture of at least two types of low foaming nonionic surfactants are contained in the composition in an amount of about 0.1 to 10 g/
An aqueous cleaning composition according to any one of the preceding clauses 1 to 4, wherein the aqueous cleaning composition is present. 7 One type or a mixture of at least two types of low foaming nonionic surfactants are contained in the composition in an amount of about 0.2 to 0.8 g/
An aqueous cleaning composition according to any one of the preceding clauses 1 to 4, wherein the aqueous cleaning composition is present. 8 (a) Approximately 1 to 10 g of sulfuric acid to the aluminum surface,
Hydrofluoric acid about 0.005 to 0.1 g/and alkali metal salt of 2-butoxyethoxyacetic acid about 0.1 to 10 g/
and (b) cleaning the aluminum surface to remove the cleaning solution. 9 2-butoxyethoxyacetic acid alkali metal salt is sodium 2-butoxyethoxyacetate,
The method of item 8, wherein about 0.2 to 0.8 g/g is present in the cleaning solution. 10. The method of paragraph 8, wherein the aqueous cleaning solution is contacted with the aluminum surface by spraying the solution onto the surface. 11. The method of item 8, wherein the solution temperature is maintained in the range of about 115-145°. 12. The method of item 8, wherein the cleaning solution comprises about 3 to 5 g of sulfuric acid, about 0.01 to 0.03 g of hydrofluoric acid, and about 0.2 to 0.8 g of sodium 2-butoxyethoxyacetate. 13. The method according to any one of paragraphs 8 to 12, wherein about 0.1 to 10 g of one or a mixture of at least two low foaming nonionic surfactants is present in the aqueous cleaning liquid. 14. The method according to any one of the preceding clauses 8 to 12, wherein about 0.2 to 0.8 g of one or a mixture of at least two low foaming nonionic surfactants is present in the aqueous cleaning liquid. 15. The method of item 13 above, wherein the aluminum surface is an aluminum can. 16. The method of item 14 above, wherein the aluminum surface is an aluminum can.