Akademik Veri Yönetim Sistemi
Tutak D., Pekarovicova A.(Yürütücü)
TÜBİTAK Projesi, 2013 - 2015
One of the most difficult recycling tasks is deinking of digital printed-paper with water based inkjet inks. The deinking of these papers is very important for the improvement of the digital printing industry. In this part of the project the manufacturer’s preferred method INGEDE Method 11p (Figure 1), which defines the universal deinking process, is used. Based on this study, two different deinking procedures were assessed. Deinked papers with better optical properties were reached with these deinking procedures, but the validity of these methods has not been clarified yet. The deinking procedures and results of this study are shown below.
Paper recovery rates continue to increase each year in most parts of the world. The recycling rate in Europe reached 70.4% in 2011. Thirteen European countries exceeded the 70% recycling rate, 12 European countries were below 60%[2]. Besides, almost 65 percent of the paper consumed in the U.S. has been recovered for recycling in 2013. That’s great news for the environment and for the paper industry.[3]
For solving the problems related to insufficient raw materials, the sustainable recycling technologies should be developed rather than concentrating on sustainable forestry practices. In this sense, extracting all materials from waste papers with economical and environmentally friendly methods are extremely important [4].
With the development of digital technology, Digital printing technologies are gaining a growing share of the market [5], digital printing has already become a necessary printing method. Compared with the other traditional printing methods, digital printing is easy to control and convenient [6]. Nowadays, nearly all houses or offices have a digital printer. Because of this, waste paper rate is increasing day by day. Recycling of this waste paper is very important. As is known, recycled fibers play a very important role today in the global paper industry as a substitute for virgin pulps
Paper recycling is directly connected with the printing industry. Generally preferred method for removing detached particles from the pulp is by flotation, but this technique is only effective for particles having size diameter ranges of 20 to 150 microns [7]. The toner particle size of Liquid Electrophotography (LEP) digital presses that uses an LEP) ink is very small, 1-2 microns, which is smaller than dry toners [8]. However, nonimpact inks are very difficult to remove using conventional deinking methods. These inks are usually water-based with a hydrophilic character thus making them very difficult to remove from the pulp slurry [9].
The major challenge of paper recycling is to remove ink from fiber. Water based flexography and inkjet prints are two typical inks that are hard to be removed via flotation deinking [10]. For an effective deinking, it is very important to prevent ink particles redeposition onto the fibers prior to removal [11]. This ink removal process can be summarized by two main stages. Initially, the interaction of ink particles with air bubbles occurs. This event is generally believed to be governed by the size and the hydrophobicity of both ink and bubbles [12], secondly, the bubble / ink heterostructures flow in the froth, where the efficient upward flow of ink particles is closely correlated to the stability of froth phase and the adhesion energy of ink particles to air bubbles [13].
Deinking agent often include fatty acids, non-ionic surfactants, or mixtures of both spaces, but these materials can be change or modify with different chemicals and better results can be obtained. The purpose of these studies is to achieve a better paper.