ECOLOGICAL PREPAINT TREATMENT OF ALUMINIUM ... - Aluplanet

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friendly chemical technologies is one of the significant factors driving these new treatment methods. BioChemical Cleaning A new advance in aqueous alkaline cleaning has been achieved through the combination of latest generation inorganic and organic chemical compounds in synergy with biotechnology. Applicators would like to reduce their energy consumption, so it would be desirable to have lower temperature operating cleaners. This has been realised by the use and optimisation of increased surfactant combinations with highly active dispersants. These new formulations displace and emulsify surface soils at lower operating temperatures. At the same time there is a need for longer life of process solutions. Through the process of bioremediation, complex organic molecules such as oils, are converted into less complex, non-hazardous substances such as carbon and water. This means that a wide range of oils and soils will be consumed and eliminated from the working solution. The latest generation BioChemical cleaners utilise microbes found in nature which have been selected for their benefits to humans. They play a fundamental role in the transformation of matter in various fields and are increasingly found in industrial applications. Extensively used in the production of foods and beverages, their use has grown considerably in the chemical and pharmaceutical industries as well as modern waste water treatment plants. Under aerobic conditions, biodegradation of organic compounds will naturally occur and an effective degradation of matter can be achieved, as illustrated in slide 5. The interaction of an active biomass over time with larger organic molecules results in the formation of many smaller molecules and increased biomass. This process known as Bioremediation enables the continual repetition of this reaction on prolonged contact, creating smaller organic molecules some of which will be broken down many times an be transformed into more nicrobes, small amounts of carbon dioxide and water. This ability to continue reacting over time is one of the unique benefits from biotechnology. This approach is now successfully used in a number of industrial applications such as paint pretreatment, paint overspray treatment and waste treatment. BioChemical cleaning Latest generation chemistry Aerobic microbes Bioremediation TIME CO 2 Water Oil at surface Oil, Water Surfactant Emulsion BIOMASS Surfactant Slide 5: illustration of the bioremediation process The combination of latest cleaning chemistry and biotechnology ensures consistent performance, optimum process efficiency and exceptionally long solution working life. This avoids the need for regular solution dumps, conserving both chemistry and water, whilst drastically reducing waste disposal needs. Further improvements can be achieved when BioChemical cleaners are combined with dedicated filtration equipment. This synergy
etween product and equipment enables the working solution to be continuously rejuvenated Performance improvement BioChemical & Equipment Synergy with equipment and chemistry BioFilter unit for optimum performance Consistent and optimum performance Extended working solution life and replenished, as referenced by slides 6 & 7. Slide 6: BioFilter Slide 7: optimum performance Organic Dry In Place Organic Dry In Place (ODIP) coatings are formed by drying a variety of aqueous chemistries directly onto a cleaned metal surface. Operating at room temperature, the coating chemistry is completely free of phosphates, chromium and solvents. Bulk spray or immersion applied, it will deposit a thin coating onto a range of metallic substrates such as steel and aluminium by chemical bonding, thereby reducing the influence of the substrate material. ODIP means there is no need for water rinsing, just an oven dry after application. This eliminates the need for a final water rinse, reducing energy and water consumption. Since the system does not rely on a precipitation or conversion reaction, there are no sludges and scales produced as by-products, which avoids extensive equipment cleaning. This new technology is rapidly being introduced as a replacement for iron phosphate. Adhesion and corrosion resistance is equivalent or better and is ideal if the primary performance criteria is paint adhesion and when there are a limited number of process tanks available, for example in a three stage spray line. This has found numerous applications throughout the paint and powder coating sector, for a number of substrates including aluminium. In domestic appliances it is used for the painting of white goods like cookers and washing machines. In automotive it is gaining acceptance for motorcycle parts made from wrought alloys and for car braking systems on cast alloys. ODIP coatings are applied in conventional paint pretreatment lines by spray or immersion, without the need for capital investment. The simplified bonding mechanism is shown on slide 8. Aluminium is first cleaned, this would typically be a non-etch alkaline cleaner. Following water rinsing, the ODIP coating solution is applied by either spray or immersion. As there are no precipitation or conversion reactions taking place, it is sufficient to fully wet the surface. The chemistry contains active functional groups which chemically bond to the metal oxide sites during oven drying. Following successful pretreatment, an organic coating such as powder coat, can be directly applied to the substrate surface. The powder contains active bonding sites which chemical combine with the coating during the oven curing process. This is a simplified way to show how the technology achieves highly adherent and superior bonding between metallic substrates and paint or power type coatings.
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ECOLOGICAL PREPAINT TREATMENT OF ALUMINIUM ... - Aluplanet

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