Vegetable oil esters used in the manufacture of nameplates
A small and medium size enterprise substituted in a first step tetrachloroethylene and then hydrocarbon solvents with esters based on coconut oils. The esters are used to remove bitumen layers protecting defined areas of the nameplates from acid treatment and lacquering.
The substituted solvents have hazardous properties according to their harmonised classification. Tetrachloroethylene and naphtha (petroleum), hydrodesulfurized heavy, are included in the Substance Database according to SUBSPORT Screening Criteria (SDSC). The alternative solvent, esters based on coconut oil (Estisol 242), is not classified. Diethylene glycol monobutyl ether (CAS 112-34-5) still used in the final cleaning step has a harmonised classification (R36, H319).
Kilian Industrieschilder, a family business based in Hamburg with around 30 employees, manufactures nameplates mainly for machines, vehicles and equipment.
Metal plates are treated with acid before being lacquered. To protect defined areas of the plates from acid and lacquer they are covered with a layer of bitumen. The unprotected areas are deepened by the acid treatment. In the following step the lacquer is applied at 130°C. Finally, the bitumen layer with the burned in lacquer has to be removed from the plates to uncover the untreated areas without damaging the lacquering of the other areas.
This was previously achieved using tetrachloroethylene as solvent. Due to legislative requirements and the location of the production facilities in a water protection area the halogenated solvent was replaced by two hydrocarbon solvents.
In a first cleaning step the plates were incubated with solvent naphtha , medium aliph. (Kristallöl 30), for 12 hours. The solvent penetrated the lacquer and caused the bitumen to swell and break the lacquer layer. The swelled bitumen was then removed manually. To get rid of residual bitumen a second solvent naphtha (petroleum), hydrodesulfurized heavy (Kristallöl 60), was applied. The final cleaning step was done using butyl diglycol (diethylene glycol monobutyl ether, CAS 112-34-5) and water to get surfaces free of grease.
Now the enterprise uses esters based on coconut oil (Estisol 242) as substitute for the two hydrocarbon solvents. The incubation time in the first cleaning step could be reduced from 12 hours to 10 minutes. The quality of the plates’ lacquered areas is not affected. The esters have a milder smell than the solvents used before.
Kilian is certified by a Technical Inspection Agency (TÜV-Norddeutschland) according to § 19 of the Water Resources Act and the only company in Germany that is allowed to produce in a water protection area.
The esters based on coconut oil are a safer and even more efficient solvent for the described application.
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KILIAN INDUSTRIESCHILDER GMBH
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