Tests to deink inkjet paper are successful
The Digital Print Deinking Alliance (DPDA) has shared the first of a series of scientific research investigations into the deinkability of inkjet printed papers. In a study conducted by Centre Technique du Papier (CTP) of Grenoble, France, a leading research organisation and expert in the field of recycling technologies, inkjet prints were successfully deinked in a procedure designed to replicate a typical European mixed grade waste paper recycling system.
?The test samples were printed using standard aqueous dye-based inkjet inks on uncoated woodfree paper. DPDA members prepared blind samples using three representative dye-based inksets for the study and tested under conditions designed to be representative of current deinking technology for processing mixed grades of recovered paper.? ?
In the study, nearly all colorants were successfully deinked when hydrosulphite bleach was added after the re-pulping process. In one case, ink colorants were successfully deinked using peroxide only, which is a typical chemical used in the re-pulping step. In both cases, the bleached pulp met the deinked pulp quality requirements. ?
It has been recently suggested that inkjet printed papers are not deinkable according to laboratory test conditions known as INGEDE Method 11. This lab test was primarily conceived to compare the deinking performance of gravure and offset prints on wood-containing papers. INGEDE Method 11 is sometimes cited as a simple lab-scale test to compare deinking performance of various printing technologies. "Method 11 may not be appropriate for all aqueous based inks, since the test is primarily a single step flotation test. With dye based inks, there is no ink particle to float, hence the futility of trying to meet this requirement," said Dr Matthias Fromm, R&D manager at Oce Printing Systems.?