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Title
Effects of pulping temperature and accelerated ageing on optical properties of digital duplicator print handsheets
Authors
Zeljka Barbaric-Mikocevic Ivana Plazonic and Vesna Dzimbeg-Malcic
Received
November 6, 2009
Published
Volume 44 Issue 10 November-December
Keywords
digital duplicator prints, chemical deinking by washing, washing temperature, ageing, optical
Abstract
Deinking efficiency and optical stability of digital duplicator print handsheets have been examined. During chemical deinking through washing, fatty alcohol ethoxylate C 13-15 with 7 EO groups has been used as a surfactant. The pulping temperatures were changed, while the other washing process conditions, including surfactant concentration, pulping and homogenization time, were carefully chosen and kept constant. Deinking efficiency was monitored through the optical properties of the laboratory handsheets in the visible part of the electromagnetic radiation. The best optical performance of a handsheet was achieved at the lowest disintegration temperature. The optical stability of the handsheets obtained at different disintegration temperatures was tested by accelerated ageing. The changes in the values of relative reflectance and scattering and absorption coefficients, due to the interaction of UV and visible electromagnetic radiation with the samples, were monitored. The results obtained point out that optimal deinking efficiency and optical stability are achieved under energy-saving (low disintegration temperature, which is unusual for common deinking) and environmentally friendly (only surfactant – without other deinking chemicals – has been used) process conditions.
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