EP0157382A1 - 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 PDFInfo
- Publication number
- EP0157382A1 EP0157382A1 EP85103789A EP85103789A EP0157382A1 EP 0157382 A1 EP0157382 A1 EP 0157382A1 EP 85103789 A EP85103789 A EP 85103789A EP 85103789 A EP85103789 A EP 85103789A EP 0157382 A1 EP0157382 A1 EP 0157382A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ppm
- cleaning
- solution
- cleaned
- cleaning solution
- 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.)
- Granted
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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 whose boron content compared to the free fluoride content is greater than the stoichiometric requirement for the formation of BF 4 - 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 to exceed the need for BF4 formation.
- the aluminum surfaces are cleaned with a solution which contains 20-50 ppm free fluoride.
- free fluoride used here and in the preceding refers to the fluoride which is not bound in a complex manner, for example 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 the details - including the measuring method - is described.
- 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 required cleaning in order to remove metal particles, stains, lubricants and the like while taking into account the desired surface properties, the degree of etching and the type of subsequent treatment that follows.
- the boron content is adjusted to the required stoichiometric excess in accordance with the aforementioned definition.
- 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.
- hydrofluoric acid is used as the source of the fluoride component, it may 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. It is preferred to work with a cleaning solution whose pH 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.
- cleaning solution to be used according to the invention is increased if, in a further preferred embodiment, cleaning is carried out with a cleaning solution which additionally contains surfactant, preferably up to 10 g / l, in particular in an amount of 0.1-5 g / 1. Depending on the degree of contamination of the aluminum surface, good results can be achieved with 0.5 - about 1 g / 1 surfactant.
- a suitable defoaming agent in order to avoid undesirably high foaming, in particular 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. These The patent describes the combination of surfactants of certain hydrocarbon 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 combination of surfactants ensures the removal of a wide variety of organic compounds and contaminants 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.
- surfactant AR 150 from Hercules, Inc. (ethoxylated abietic acid with about 15 etho groups);
- Pegosperse 700-TO from Glyco Chemicals, Inc. (ethoxylated abietic acid with about 14-16 etho groups); Triton CF-10 from Rohm + Haas Co. (alkylaryl polyether with a carbon chain of about 16 carbon atoms with about 16 etho groups);
- Pluronic L-61 from BASF Wyandotte, Inc. (condensation product of ethylene oxide and propylene oxide);
- Antarox LF-330 from GAF Corporation (alkylpolyethoxyethanol);
- Antarox BL-330 from GAF Corporation (alkylpolyethoxyethanol);
- Igepal Ca-630 from GAF Corporation (alkylphenoxypolyethoxyethanol);
- Plurafac D-25 from BASF Wyandotte, Inc. modified oxyethylated straight-chain alcohol
- Triton X-102 from Rohm + Haas Co. (octylphenoxypolyethoxyethanol);
- Plurafac RA-30 from BASF Wyandotte, Inc. (modified, ethylated, straight-chain alcohol);
- Polytergent S-505 LF from Oline Corporation modified polyethoxylated straight-chain alcohol
- Triton DF-16 from Rohm + Haas Co. (modified polyethoxylated straight-chain alcohol);
- 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 compounds dung, which is characterized in that its boron content compared to the free fluoride content is greater than the stoichiometric requirement for the formation of BF4- and corresponds to a pH value of less than 3.5.
- 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.
- a further advantageous embodiment provides cleaning solutions whose surfactant content is up to 10 g / 1, in particular 0.1-5 g / 1.
- 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
- 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 with 5.5 - 6 represents a good result.
- the rating with 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.
Landscapes
- 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)
- Materials For Medical Uses (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Chemical Treatment Of Metals (AREA)
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 true EP0157382A1 (fr) | 1985-10-09 |
EP0157382B1 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) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0230903A2 (fr) * | 1986-01-21 | 1987-08-05 | HENKEL CORPORATION (a Delaware corp.) | Procédé de nettoyage de récipients en aluminium |
EP0234425A2 (fr) * | 1986-02-18 | 1987-09-02 | HENKEL CORPORATION (a Delaware corp.) | Procédé de nettoyage de récipients en aluminium |
WO1993023590A1 (fr) * | 1992-05-14 | 1993-11-25 | Henkel Corporation | Procede de nettoyage de l'aluminium a basses temperatures |
EP0877833A1 (fr) * | 1996-01-29 | 1998-11-18 | Henkel Corporation | Inhibiteur desoxydant l'aluminium, compositions et processus s'y rapportant |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2961355A (en) * | 1958-01-20 | 1960-11-22 | Dow Chemical Co | Method of and solvent for removing inorganic fluoride scale deposits |
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 |
Family Cites Families (4)
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 |
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 |
-
1985
- 1985-03-29 AU AU40533/85A patent/AU4053385A/en not_active Abandoned
- 1985-03-29 EP EP85103789A patent/EP0157382B1/fr not_active Expired
- 1985-03-29 DE DE19853511514 patent/DE3511514A1/de not_active Withdrawn
- 1985-03-29 ZA ZA852407A patent/ZA852407B/xx unknown
- 1985-03-29 AT AT85103789T patent/ATE36355T1/de not_active IP Right Cessation
- 1985-03-29 DE DE8585103789T patent/DE3564293D1/de not_active Expired
- 1985-04-01 BR BR8501513A patent/BR8501513A/pt unknown
- 1985-04-02 GB GB08508536A patent/GB2157323A/en not_active Withdrawn
- 1985-04-02 CA CA000478153A patent/CA1223182A/fr not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
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 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0230903A2 (fr) * | 1986-01-21 | 1987-08-05 | HENKEL CORPORATION (a Delaware corp.) | Procédé de nettoyage de récipients en aluminium |
EP0230903A3 (en) * | 1986-01-21 | 1989-02-08 | Parker Chemical Company | Process for cleaning aluminium containers |
EP0234425A2 (fr) * | 1986-02-18 | 1987-09-02 | HENKEL CORPORATION (a Delaware corp.) | Procédé de nettoyage de récipients en aluminium |
EP0234425A3 (en) * | 1986-02-18 | 1989-02-15 | Parker Chemical Company | Process for cleaning aluminium containers |
WO1993023590A1 (fr) * | 1992-05-14 | 1993-11-25 | Henkel Corporation | Procede de nettoyage de l'aluminium a basses temperatures |
EP0877833A1 (fr) * | 1996-01-29 | 1998-11-18 | Henkel Corporation | Inhibiteur desoxydant l'aluminium, compositions et processus s'y rapportant |
EP0877833A4 (fr) * | 1996-01-29 | 1999-04-21 | Henkel Corp | Inhibiteur desoxydant l'aluminium, compositions et processus s'y rapportant |
Also Published As
Publication number | Publication date |
---|---|
DE3564293D1 (en) | 1988-09-15 |
CA1223182A (fr) | 1987-06-23 |
BR8501513A (pt) | 1985-11-26 |
DE3511514A1 (de) | 1985-10-10 |
GB8508536D0 (en) | 1985-05-09 |
GB2157323A (en) | 1985-10-23 |
ZA852407B (en) | 1985-11-27 |
EP0157382B1 (fr) | 1988-08-10 |
ATE36355T1 (de) | 1988-08-15 |
AU4053385A (en) | 1985-10-10 |
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