Paper Technology International 2020 - Journal - Page 60

PAPERTECHNOLOGYINTERNATIONAL
Assuming a constant sticky inlet load to coarse screening of
approximately 21,000 mm²/kg measured according to ISO 15
360 - 2/ TAPPI T277, and assuming that the accept quality
was 970 mm²/kg for the short fiber (SF) fraction of an OCC
stock preparation plant and 3700 mm²/kg for the long fiber
(LF) fraction, both measured according to ISO 15 360 - 2/
TAPPI T277, the sticky reduction was 91.4% at a mass split in
fractionation of 30% LF/ 70% SF, see Figure 4.
Transferring these measurement results to DIN SPEC 6745
results using the approximation function given in Figure 3,
the sticky reduction drops to 84.9%, although the process
technology did not change.
Since the paper industry is striving for increased sticky
reductions, the results shown in Figure 3 may require a paradigm
shift to accepting lower sticky reductions due to the sticky
measurements performed according to DIN SPEC 6745 compared
those performed according to ISO 15 360 – 2/ TAPPI T277 for the
same OCC samples.
Summary
In this paper, the experiences made by Voith Paper performing sticky measurements according to DIN SPEC 6745, applying the NIR
measurement technique, were presented and discussed in detail. Today’s common method of performing sticky measurements according to
ISO 15 360-2 is well established and proven within the paper industry. However, due to the high number of manual working steps, the sticky
measurement technique described in ISO 15 360-2 is prone to error. Performing sticky measurements according to DIN SPEC 6745 has
several benefits that are summarized as follows:
•
•
Reduced time and labor effort to prepare samples with increased accuracy and reliability of sticky measurement results
Easy sample preparation by making hand sheets on globally available equipment
Since sticky measurements according to DIN SPEC 6745 differ from those values known to papermakers using ISO 15 360-2,
the paper industry needs to get used to these new values and their impact on sticky reduction values on unchanged process technology.
Certainly, this will require a change process; but, the benefits summarized above due to the application of the sticky measurements
performed according to DIN SPEC 6745 will outweigh for the paper industry in the long term.
Besides the benefits summarized in this paper, applying the NIR sticky measurement technique according to DIN SPEC 6745 is
possible for the applications described as follows:
•
•
Determining the sticky load of final paper samples
Studying and evaluating the recyclability of packaging papers in the future using the information about non-tacky components
and stickies determined according to DIN SPEC 6745
Due to the availability of the technical rule, DIN SPEC 6745 “Paper, board and pulps - Recycling - Determination of stickies and nontacky contaminants in recycled pulps and papers applying near-infrared measurement” and commercially available measurement equipment,
measuring stickies using the NIR measurement technique has the potential to set a new standard within the paper industry.
References
[1]
ISO 15360-2: 2015, Recycled pulps - Estimation of Stickies and Plastics - Part 2: Image analysis method
[2]
TAPPI T277, Macro Stickies Content in Pulp: the “Pick-up” Method
[3]
INGEDE 4, April 2013, Macro Stickies Content in Pulp: the “Pick-up” Method
[4]
DIN SPEC 6745:2020-04, Paper, board and pulps - Recycling - Determination of stickies and non-tacky
contaminants in recycled pulps and papers applying near-infrared measurement
[5]
TAPPI T 1200, Interlaboratory evaluation of test methods to determine TAPPI repeatability and
reproducibility
[6]
TAPPI T 1206, Precision statement for test methods
[7]
TAPPI, Macro stickies content in pulp: the “pick-up” method, Five-year review of T 277 pm-99 to upgrade
as an Official Method, March 2007.
[8]
L. Haman; New metrological options for monitoring contaminants in stock preparation, PTS Seminar AM 1865 - Modern Analytical
Methods in Paper Technology, 2018
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