Deinkability of UV curing printing inks
Beatrix Genest, Carolin Sommerer (SID)
Antje Kersten, Dr. Hans-Joachim Putz (PMV)
Sächsisches Institut für die Druckindustrie GmbH, Leipzig
Papierfabrikation und Mechanische Verfahrenstechnik, Technische Universität Darmstadt
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AiF-Project 20476 BG, 01.01.2019 - 31.12.2020
UV inks in sheet-fed offset printing –Deinkability and fate of substances of health concern
Targets: Objective evaluation of the deinkability of UV printing products Effect of printing conditions (ink, paper quality, curing technology) Comparison between UV printed and conventional offset printed products
with and without UV varnish Determination of measures to optimise printing process conditions regarding
deinkability Evaluation of the impact of increasing proportions of UV printing products on
the quality of aper for recycling
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Phase 1: Commercial UV prints
38 printed products fromdifferent printers
28 print products tested
Deinkability Test: 17 passed 11 failed
Reason: Dirt speck area
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Phase 1: Commercial UV prints
Influencing Factors on Deinkability
No effect of paper quality Problems with some samples cured with mercury lamps and some samples
cured with iron-doped mercury lamps No correlation between hardening degree and Deinkabiliy Score Different results for different ink formulations
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Phase 2: Pilot Scale Test on Sheet-fed Press
Test Conditions
Sheet-fed Press SM DC 74-5+L UV technologies: mercury lamp, iron-doped mercury lamp, UV LED 6 Substrates: coated paper (glossy/matt), uncoated paper 16 UV inks, 3 conventional inks 3 UV varnishes (in combination with UV ink and conventional ink) Variation of UV dosage Variation of pressure and composition of dampening solution (with/without
IPA) At all 180 variations
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Phase 2: Pilot Scale Test on Sheet-fed Press
Test Form(single-sided print)
Version 1: (small picture)Picture, text, screen tintsAverage ink coverage 40%
Version 2: (big picture)Pictures, screen tintsAverage ink coverage 200%
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Phase 2: Pilot Scale Test on Sheet-fed Press
Deinkability Results
Test Form version 1: all samples with good deinkability Test Form version 2: differentiated results ~ 40% not deinkable Reason: Dirt speck area
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Phase 2: Pilot Scale Test on Sheet-fed Press
Influence on Deinkability Results Paper quality: - Ink formulation:
0102030405060708090
100
Pape
r A
Pape
r B
Pape
r C
Pape
r E/F
Pape
r G
Dei
nkin
g Sc
ore
Results depending on paper, inks 5,10,12,13,15,16
0102030405060708090
100
Ink
2In
k 3
Ink
5In
k 6
Ink
7In
k 8
Ink
9In
k 10
Ink
11In
k 12
Ink
13In
k 14
Ink
15In
k 16
Ink
17In
k 18
Ink
19
Dei
nkin
g Sc
ore
Results depending on ink formulation, all papers
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Phase 2: Pilot Scale Test on Sheet-fed Press
Influence on Deinkability Results
UV technology: Best results with
conventional ink Only a few tests with LE
(iron-doped mercury lamp) LED worse results
compared to the mercurylamp
0
10
20
30
40
50
60
70
80
90
100
Hg LE LED oxi
Dei
nkin
g Sc
ore
Results depending on curing technology
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Phase 2: Pilot Scale Test on Sheet-fed Press
Influence on Deinkability Results UV dosage: (samples with good deinkability)
Hardening degree correlates with UV dosage, but not with deinkability
0102030405060708090
100
2x16
0W C
2x10
0W C
2x80
W C
2x60
W C
1x80
W C
2x16
0W F
2x10
0W F
2x80
W F
2x60
W F
1x80
W F
Dei
nkin
g Sc
ore
Results depending on UV dosage, Ink 14, Paper C Paper F
60
65
70
75
80
85
90
95
100
2x16
0W
2x10
0W
2x80
W
2x60
W
1x80
W
Aush
ärtu
ng in
%
F14
50
60
70
80
90
100
2x16
0W
2x10
0W
2x80
W
2x60
W
1x80
W
Har
deni
ngD
egre
e in
%
C14
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Phase 2: Pilot Scale Test on Sheet-fed Press
Influence on Deinkability Results UV dosage: (samples with bad deinkability)
No correlation between hardening degree and deinkability
0102030405060708090
100
1x10
0% 3
1x80
% 3
1x60
% 3
1x40
% 3
2x16
0W 1
3
2x10
0W 1
3
2x80
W 1
3
2x60
W 1
3
Dei
nkin
g Sc
ore
Results depending on UV dosage, Paper A
Ink 3 (LED) Ink 13 (Hg)
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Phase 2: Pilot Scale Test on Sheet-fed Press
Deinking-Score
Hg 100 LED 100 Hg 73
UV Technology
Explanation:
Bad deinkability
Deinking, Score < 90
Good deinkability
Different results
2 3 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
A Hg 43
Hg 45 LED 37 Dosis 39‐48 Hg 95 Hg 35 Hg 100 Hg 39
Hg 41 Dosis 41‐46 Hg 73 Hg 100
B Hg 48 Hg 39Hg 98 LED 66 Hg 32 Hg 99
Hg 93 Hg 99 Hg+L1 50 LED 77 LED 54 Hg 40 Hg 29
Hg 100 IPA Hg 97
Hg 100 Hg 100 IPA Hg 100
Hg 100 IPA Hg 100 oxi 96
oxi 100 Hg+L1 69 oxi 100
C LE 48 LED 49Hg 100 LED 48 Hg 47 Hg 100 Hg 100 Hg 100 Hg 94
Hg 99 LED 50
Hg 50 Hg 70
Hg 49 Hg 72
Dosis 86‐100 Pressg 93‐100 Hg 85, 86 IPA Hg 69
Hg 100 Hg 100 Hg 92
IPA oxi 92 L1, L2, L3 Hg 97‐100
E Hg 100
Hg 89 LED 86 IPA: Hg 95 LED 100
IPA Hg 100
oxi 100 IPA oxi 100 oxi 62
F Hg 77 LED 61
Hg 98 LE 100 Hg 93 Hg 100
Hg 100 LED 100
Hg 100 LED 100 Hg 73
Hg 99 Hg 100
Hg 100 Hg 100 Dosis 100
Hg 83 Hg 100
Hg 50 Hg 60
G
Hg 100 Dosis 100 LED 88 LED 100 Hg 100 Hg 46 Hg 67 Hg 100 Hg 77
Coated
Paper
Uncoated Paper
Ink
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Phase 2: Pilot Scale Test on Sheet-fed Press
Impact on Deinkability Results Summary
Parameter EffectInk formulation ++Paper quality oCoated/uncoated paper +UV dosage, hardening degree oUV technology +Ink coverage ++Pressure, dampening solution oUV varnish +
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Conclusions
Main influencing factors are ink formulation and ink coverage UV dosage/energy consumption induced by requirements of
printing process UV varnishes can influence the deinkability (both UV inks and
conventional inks) For general evaluation of deinkability a test form with defined ink
coverage and paper quality has to be determined
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Thank you for your attention!
Sächsisches Institut für die Druckindustrie GmbH
Mommsenstraße 2, 04329 Leipzig
Telefon: +49(0) 3 41/2 59 42-0
Telefax: +49(0) 3 41/2 59 42-99
E-Mail: [email protected]
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