EP0157382B1 - Procédé et solution de nettoyage aqueuse acide pour le nettoyage de surfaces d'aluminium - Google Patents

Procédé et solution de nettoyage aqueuse acide pour le nettoyage de surfaces d'aluminium Download PDF

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Publication number
EP0157382B1
EP0157382B1 EP85103789A EP85103789A EP0157382B1 EP 0157382 B1 EP0157382 B1 EP 0157382B1 EP 85103789 A EP85103789 A EP 85103789A EP 85103789 A EP85103789 A EP 85103789A EP 0157382 B1 EP0157382 B1 EP 0157382B1
Authority
EP
European Patent Office
Prior art keywords
solution
cleaning
ppm
amount
cleaned
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85103789A
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German (de)
English (en)
Other versions
EP0157382A1 (fr
Inventor
Laura A. Berry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Henkel Corp
Original Assignee
Parker Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Parker Chemical Co filed Critical Parker Chemical Co
Priority to AT85103789T priority Critical patent/ATE36355T1/de
Publication of EP0157382A1 publication Critical patent/EP0157382A1/fr
Application granted granted Critical
Publication of EP0157382B1 publication Critical patent/EP0157382B1/fr
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/12—Light metals
    • C23G1/125—Light metals aluminium

Definitions

  • the invention relates to a method for cleaning aluminum surfaces with acidic, aqueous solutions which contain a soluble boron compound and a soluble fluoride compound, and to an aqueous, acidic cleaning solution containing soluble boron and soluble fluoride compound.
  • Aluminum containers have found widespread use and are used in particular for packaging food and beverages, such as soft drinks and beer. It is common practice in the manufacture of such containers to first punch round disks out of aluminum sheet, to bring them into a preliminary cup shape with suitable devices and finally to deform them in one or more stages by pulling and smoothing them into the final can. The cans are then trimmed and subjected to various cleaning and treatment stages. The conclusion is usually the application of an inner varnish and a decorative outer coating.
  • various lubricants and cooling lubricants are used which - together with fine metal particles that are formed during the shaping process - remain in certain quantities. It is essential that such lubricant residues and metal particles be removed before the containers are subjected to a chemical treatment.
  • the object of the invention is to provide methods and aqueous acidic cleaning solutions for cleaning aluminum surfaces which do not lead to the known disadvantages, in particular those mentioned above, but are easy to carry out or have a high level of economy with a good cleaning effect and no taste impairment.
  • the object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the aluminum surface is cleaned with a solution which contains surfactant, the boron content of which is greater than the free fluoride content than the stoichiometric requirement for the formation of BF 4 - corresponds and which has a pH value less than 3.5.
  • the cleaning solution used usually contains less than 4 g / 1 free fluoride.
  • the aluminum surfaces are cleaned with a cleaning solution which contains at least 10 ppm free fluoride, in particular 10-100 ppm free fluoride.
  • the content of soluble boron compound, such as borate, is adjusted so that it exceeds the need for BF 4 formation.
  • the aluminum surfaces are cleaned with a solution which contains 20-50 ppm free fluoride.
  • free fluoride refers to the fluoride that is not complex bound, e.g. in the form of fluoroborate, silicate and aluminate, which increasingly forms during use of the cleaning solution.
  • the "free fluoride” is the bath component, which is measured by a specific fluoride-sensitive electrode potentiometrically against a standard solution with 40 ppm fluoride at pH 1.1 and a temperature of 26.7 ° C.
  • a suitable fluoride-sensitive electrode is described, for example, in US Pat. No. 3,431,182, to which reference is made for details, including the measurement method.
  • the cleaning solution used in the process according to the invention contains a boron compound, the concentration of which depends on the concentration of the free fluoride present.
  • boron compound the concentration of which depends on the concentration of the free fluoride present.
  • Boric acid and its simple alkali and ammonium salts are particularly suitable sources of the boron compound.
  • the BF 4 anion does not necessarily have to be formed in the cleaning solution. It can be used as a basis for adjusting the relative concentration of boron to free fluoride.
  • the free fluoride content is determined by the extent of the intended or necessary cleaning in order to remove metal particles, stains, lubricants and the like, while taking into account the desired surface quality, the degree of etching and the type of subsequent treatment that follows.
  • the boron content is reduced to the required stoichiometric excess in accordance with the above definition set.
  • the aluminum surface is cleaned with a cleaning solution whose stoichiometric excess of boron compared to the free fluoride is at least 4 ppm, preferably up to 200 ppm. An excess over the stoichiometric requirement within a range of 10-75 ppm is particularly advantageous.
  • the pH of the cleaning solution can be adjusted by any suitable inorganic or organic acid that is soluble and therefore compatible with it. Mineral acids, especially sulfuric acid, are particularly suitable. If hydrofluoric acid is used as the source of the fluoride component, it can provide all or part of the need for hydrogen ions. If the fluoride is introduced via alkali or ammonium fluoride compounds, correspondingly higher amounts of other acids are required.
  • the pH value is capped at 3.5, because otherwise the treatment time required for thorough cleaning would increase too much.
  • a cleaning solution is preferably used, the pH of which is 1-2.
  • the optimal pH value depends on the concentration of the components of the cleaning solution, the application temperature and the duration of the treatment. Depending on the fluoride content, pH values below 1 are often associated with an undesirable etching removal and thus a matt appearance of the aluminum surface. In cases where a shiny metallic surface is desired, pH values that are so low are therefore avoided.
  • the effect of the cleaning solution to be used according to the invention is particularly favorable if, in a further preferred embodiment, cleaning is carried out with a cleaning solution containing up to 10 g / l surfactant, in particular surfactant in an amount of 0.1-5 g / l. contains. Depending on the degree of contamination of the aluminum surface, good results can be achieved with 0.5 to about 1 g / 1 surfactant.
  • a suitable defoaming agent in order to avoid undesirably high foaming, especially when using the cleaning solution in a spraying process.
  • a particularly preferred cleaning solution contains the surfactant combination described in US Pat. No. 3,969,135.
  • This patent describes the combination of surfactants of certain hydrocarbons and abietic acid derivatives, it being possible to use the surfactants in amounts of 0.1-50 g / l, preferably in amounts of 0.5 to 2.0 g / l.
  • the use of this surfactant combination in particular ensures the removal of a wide variety of organic compounds and dirt on the aluminum surface and increases the effectiveness and applicability of the cleaning solution.
  • surfactants can be used which are of the non-ionic, anionic or cationic type.
  • Nonionic surfactants are preferred.
  • the method according to the invention can be used in the usual way for the treatment of the aluminum surfaces.
  • Use in the spraying process is particularly advantageous when aluminum containers are to be cleaned and the aim is to clean both the inside and outside of the container.
  • the cleaning solution is usually applied at a temperature above the cloud point of the surfactant used.
  • the duration of the treatment of the aluminum surfaces depends on the degree of contamination and can in extreme cases be up to 10 minutes.
  • the duration of treatment is normally from 10 seconds to 5 minutes.
  • a satisfactory cleaning result can also be achieved with a duration of less than 2 minutes.
  • the invention also relates to an aqueous acidic cleaning solution for cleaning aluminum surfaces containing soluble boron and soluble fluoride compound, which thereby is characterized in that its boron content compared to the content of free fluoride is greater than the stoichiometric requirement for the formation of BF 4 - corresponds, it has a pH value less than 3.5 and contains surfactant.
  • Preferred embodiments of the cleaning solution provide a free fluoride content of at least 10 ppm, in particular 10-100 ppm, and an excess of boron over the free fluoride of at least 4 ppm, preferably up to 200 ppm.
  • Cleaning solutions with a free fluoride content of 20-50 ppm and cleaning solutions with a pH of 1-2 are also very advantageous.
  • Another advantageous embodiment provides cleaning solutions whose surfactant content is up to 10 g / l, in particular 0.1-5 g / l.
  • Stage 1 includes a prewash with a solution from the second stage in countercurrent with a pH of 2.5-3.
  • the cleaning solution according to the invention is used in the second stage, the boron concentration depending on the concentration free fluoride can be regulated in order to test the effectiveness of the taste impairment.
  • Level 3 represents a 3-fold rinse level.
  • Level 4 forms a commercially available alkaline cleaner with subsequent rinsing.
  • Level 5 is again a triple water rinse level.
  • Stage 6 consists of a double water rinse stage, with demineralized water being used in the last section.
  • Aluminum containers that had undergone the aforementioned treatment sequences were evaluated by a panel of taste experts, in which the influence of the cleaning process on the taste of the beer was determined.
  • Freshly brewed and unpasteurized beer served in a glass served as a benchmark.
  • the same beer was placed in differently treated aluminum containers for 15 minutes, then tasted and compared to the unpackaged beer.
  • the beer serving as a benchmark has a value in the range of 3-4.
  • the most advantageous is the one whose content comes closest to the unpacked beer serving as benchmark.
  • the assigned grades were the weighted average of 8 individual grades that had been assigned by the taste experts. In accordance with the usual taste assessment, they take into account impressions such as oily, woody, and evaluate the aftertaste, bitterness, etc.
  • a rating of 6 - 6.5 is just about acceptable.
  • the rating of 5.5 - 6 represents a good result.
  • the rating of 5 - 5.5 stands for an excellent result, in which practically equivalence with the evaluation standard is achieved . It should be taken into account that values below about 5 are considered so perfect that there are doubts about the grading.
  • the aqueous acidic cleaning solution in the 2nd stage of the washing plant was continuously monitored over a period of 6 days with regard to the nature of the solution and process parameters.
  • the boron concentration caused in the form of boric acid introduced was changed and a rating for the treated doses was assigned to the respective concentration.
  • the aqueous acidic cleaning solution was applied at a temperature of 51.5 ° C and at a value for free acid of 7.5 - 9 ml (corresponding to a pH of approx. 1.4 - 1.5) and a concentration of free fluoride maintained at about 25 ppm.
  • the free fluoride was introduced in the form of hydrofluoric acid.
  • the pH was maintained by adding sulfuric acid.
  • the cleaning solution also contained 0.7 g / 1 surfactant (Trycol LF-1) and 0.7 g / 1 surfactant AR-160. Both the aqueous cleaning solution, the rinsing treatments and the pretreatment were carried out by spraying.
  • the treatment time in the 2nd stage was between 30 and 60 seconds, i.e. varied with the speed of the canning line and averaged 45 seconds.

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  • Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Detergent Compositions (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Materials For Medical Uses (AREA)

Claims (14)

1. Procédé de nettoyage de surfaces d'aluminium par des solutions aqueuses acides qui contiennent un composé soluble de bore et un fluorure soluble, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution qui contient un agent tensio- actif dont la teneur en bore par rapport à la teneur en fluorure libre est supérieure à ce qui est nécessaire stoechiométriquement pour former du BF4" et qui a un pH inférieur à 3,5.
2. Procédé selon la revendication 1, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution qui contient au moins 10 parties et de préférence de 10 à 100 parties de fluorure libre par million.
3. Procédé selon la revendication 1 ou 2, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution qui contient de 20 à 50 parties de fluorure libre par million.
4. Procédé selon la revendication 1, 2 ou 3, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution dont l'excès stoechiométrique de bore par rapport au fluorure libre représente au moins 4 parties et de préférence jusqu'à 200 parties par million.
5. Procédé selon l'une ou plusieurs des revendications 1 à 4, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution dont le pH est compris entre 1 et 2.
6. Procédé selon l'une ou plusieurs des revendications 1 à 5, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution qui contient jusqu'à 10 g d'agent tensioactif par litre.
7. Procédé selon l'une ou plusieurs des revendications 1 à 6, caractérisé en ce que l'on nettoie la surface d'aluminium par une solution qui contient de 0,1 à 5 g d'agent tensio-actif par litre.
8. Procédé selon l'une ou plusieurs des revendications 1 à 7, caractérisé en ce que l'on nettoie la surface d'aluminium à une température supérieure à 30,2°C et de préférence à une température comprise entre 37,8 et 54° C.
9. Procédé selon l'une ou plusieurs des revendications 1 à 8, caractérisé en ce que l'on nettoie la surface d'aluminium pendant une durée de 10 secondes à 5 minutes.
10. Solution aqueuse acide de nettoyage de surfaces d'aluminium ayant une teneur en composé de bore soluble et en fluorure soluble, caractérisée en ce que sa teneur en bore par rapport à la teneur en fluorure libre est supérieure à ce qui est nécessaire stoechiométriquement pour former du BF4-, elle a un pH inférieur à 3,5 et contient un agent tensio-actif.
11. Solution de nettoyage selon la revendication 10, caractérisée en ce que sa teneur en fluorure libre est d'au moins 10 parties et de préférence de 10 à 100 parties par million et son excès de bore par rapport au fluorure libre est d'au moins 4 parties et de préférence va jusqu'à 200 parties par million.
12. Solution de nettoyage selon la revendication 10 ou 12, caractérisée en ce que sa teneur en fluorure libre est comprise entre 20 et 50 parties par million.
13. Solution de nettoyage selon la revendication 10, 11 ou 12, caractérisée en ce qu'elle a un pH de 1 à 2.
14. Solution de nettoyage selon l'une ou plusieurs des revendications 11 à 13, caractérisée en ce que la teneur en agent tensio-actif va jusqu'à 10 g par litre et est notamment comprise entre 0,1 et 5 g par litre.
EP85103789A 1984-04-02 1985-03-29 Procédé et solution de nettoyage aqueuse acide pour le nettoyage de surfaces d'aluminium Expired EP0157382B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85103789T ATE36355T1 (de) 1984-04-02 1985-03-29 Verfahren und waessrige, saure reinigungsloesung zur reinigung von aluminiumoberflaechen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US59605484A 1984-04-02 1984-04-02
US596054 1984-04-02

Publications (2)

Publication Number Publication Date
EP0157382A1 EP0157382A1 (fr) 1985-10-09
EP0157382B1 true EP0157382B1 (fr) 1988-08-10

Family

ID=24385798

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85103789A Expired EP0157382B1 (fr) 1984-04-02 1985-03-29 Procédé et solution de nettoyage aqueuse acide pour le nettoyage de surfaces d'aluminium

Country Status (8)

Country Link
EP (1) EP0157382B1 (fr)
AT (1) ATE36355T1 (fr)
AU (1) AU4053385A (fr)
BR (1) BR8501513A (fr)
CA (1) CA1223182A (fr)
DE (2) DE3511514A1 (fr)
GB (1) GB2157323A (fr)
ZA (1) ZA852407B (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2719612B2 (ja) * 1986-01-21 1998-02-25 ヘンケル コーポレイション アルミニウムの洗浄方法
AU591231B2 (en) * 1986-02-18 1989-11-30 Parker Chemical Company Aluminum cleaning process
JPH07508074A (ja) * 1992-05-14 1995-09-07 ヘンケル・コーポレイション 低温でのアルミニウム清浄方法
US5637252A (en) * 1996-01-29 1997-06-10 Henkel Corporation Inhibitor for aqueous liquid deoxidizing composition and process for aluminum, with reduced etching of titanium

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB785877A (en) * 1953-02-20 1957-11-06 Acorn Anodising Company Ltd Improvements in or relating to the surface treatment of aluminium
GB891670A (en) * 1957-09-04 1962-03-14 English Electric Co Ltd Improvements in and relating to the removing of scale from silicon iron and other metals
US2961355A (en) * 1958-01-20 1960-11-22 Dow Chemical Co Method of and solvent for removing inorganic fluoride scale deposits
US3677949A (en) * 1970-09-04 1972-07-18 Enthone Selectively stripping tin and/or lead from copper substrates
US4004956A (en) * 1974-08-14 1977-01-25 Enthone, Incorporated Selectively stripping tin or tin-lead alloys from copper substrates
DE2546018A1 (de) * 1974-10-18 1976-04-22 Alusuisse Verfahren zum faerben von aluminium

Also Published As

Publication number Publication date
CA1223182A (fr) 1987-06-23
ZA852407B (en) 1985-11-27
DE3564293D1 (en) 1988-09-15
DE3511514A1 (de) 1985-10-10
GB8508536D0 (en) 1985-05-09
BR8501513A (pt) 1985-11-26
EP0157382A1 (fr) 1985-10-09
AU4053385A (en) 1985-10-10
ATE36355T1 (de) 1988-08-15
GB2157323A (en) 1985-10-23

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