Development of a waterbased cleaning process for printing machine housings
IGF 17952 N
Industrial cleaning represents a very important and economically promising future market for cleaning service companies. The cleaning of printing machine housings is a typical example: To ensure high quality printing, not only the cleanliness of the rubber rollers and cylinders located in the printing machine, but also the cleanliness of the machine housing has become a central element in quality management in recent years.
Therefore, the demands on cleaning of printing machine housings increase continuously. Both in sheetfed offset printing with UV inks and heatset web offset and newspaper printing with conventional printing inks aerosols are deposited on printing machine housings. These deposits can cause print defects due to a carryover of ink on the surface to be printed.
However, the currently used cleaning methods for removal of ink have serious drawbacks: Extensive use of organic solvents for soil removal causes expensive measures regarding work safety and environmental protection. Moreover, the large fraction of manual work results in very money, human resources and time-consuming cleaning procedures. The essential prerequisite to open up this market potential for external cleaning companies is an ecological and economic cleaning procedure for strongly adherent inkjet colours.
Therefore, target of the project was the development of a renewable soil release coating which is applied as temporary protection resp. sacrificial layer between machine housing and printing ink. The protection layer is supposed to be removed together with deposed soilings on top of the layer by a water based cleaning process without application of organic solvents. After development of suitable thixotropic soil-release-hydrogels and suitable application processing for relevant surface materials, various metal surfaces were soiled with typical printing inks. Finally, a cleaning process and treatment recommendations were worked out. This included amongst others, the observation of the migration behavior of the inks into the coating, the effect of water content, the occurrence of corrosion and the effect of fountain solution on mechanical stability.
The developed soil-release-hydrogel was proved successfully under practical conditions in three companies. Even after 6 weeks with strong soiling (resulting in closed layers) the deposited ink could be removed together with the sacrificial layer successfully from the machine parts using the developed water-based cleaning process. The amount of time needed for cleaning with the new water-based process is comparable to the conventional solvent-based cleaning process. However, the according incurred costs are lower and no organic solvents are used employing the newly developed cleaning process. The research work was performed by the wfk – Cleaning Technology Institute in Krefeld in cooperation with the Fogra-Institut e.V., Munich
The IGF-project 17952 N of the research associations Europäische Forschungsgemeinschaft Reinigungs- und Hygienetechnologie e.V., Campus Fichtenhain 11, 47807 Krefeld, and the Fogra Forschungsgesellschaft Druck e.V., Streitfeldstraße 19, 81673 München, was supported via the AiF within the funding program „Industrielle Gemeinschaftsforschung und -entwicklung (IGF)“ by the Federal Ministry of Economic Affairs and Energy (BMWi) due to a decision of the German Parliament.
The research report is available on request from FRT.