Organic, Natural Pigments as Paper Coatings · Paper x.y Speakers name 12 Acknowledges...
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Organic, Natural Pigments as Paper Coatings Jaakko Raukola Web Surface Modification 5.2
Transcript of Organic, Natural Pigments as Paper Coatings · Paper x.y Speakers name 12 Acknowledges...
Organic, Natural Pigments as Paper Coatings
Jaakko RaukolaWeb Surface Modification 5.2
Paper x.y Speakers name 2
Background: Biodegradable Fillers and Pigments for Paper Making• Mineral fillers give paper opacity, brightness and better
printability. • When 1000 kg of paper is recycled, 50-80 kg of inorganic
de-inking sludge is formed.• In Europe 86.5 million tons of paper was consumed and 46.8
million tons were recycled, 22 million tons of paper ended up for final disposal (landfill, combustion) after primary use and 6.4 million tons to other recovery options (Incineration, composting, other treatments) (CEPI statistics, year 2004)
• Assuming that fillers and pigments were organic and they could be combusted, these could replace 8 million tons of fuel oil in energy production.
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Background…• High brightness and opacity are qualities needed for good
fillers and pigments. The properties are based on effective light scattering of the material. Optimum size of a single round solid filler particle for ultimate light scattering is a half of the wave length of visible light (around 200 nm).
• The objective was to manufacture nanoscale pigments or stabilized porous filler structures of renewable materials, to be used in paper production instead of mineral materials.
• Manufacturing techniques for stabilized microcapsule filler foams and pigment particles of optimum particle size (Ø= 250 nm) with narrow particle size distribution was developed. Product properties were optimised by means of modelling.
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Surface Topography of Coated PapersUncalendered CLC-6000 samples; AP = Starch pigment
AP + GCCAP + Clay
APAP + Clay + GCC
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Surface Topography of Coated SamplesCalendered CLC-6000 AP (100pph) coating
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ISO-brightness,gloss and opacity values, calendered CLC coated papers
Opacity
71,071,572,072,5
73,073,574,0
74,575,0
75,576,0
AP-Clay AP-HC AP-HC-Clay AP Clay HC50,0
55,0
60,0
65,0
70,0
75,0
80,0
85,0
90,0
AP-Clay AP-HC AP-HC-Clay AP Clay HC
ISO% Gloss
Starch based pigment (AP) •improves brightness and it• increases gloss when used together with mineral pigments• adds opacity when used together with clay and mineralpigment mixture
(HC = GCC = Carbonate)
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Roughness of Coated Papers
0
10
20
30
40
50
60
Clay75/AP25 325 kN/m
Clay100/AP0 325 kN/m
Clay75/AP25 440 kN/m
Clay100/AP0 440kN/m
Roughness ml/min Gloss %
• mixture of pigment AP and clay improves gloss and smoothsroughness with lower calandering pressures than pure clay
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PRINT GLOSSHSWO
Print Gloss 60º
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
45,0
Cyan 100% Black 100% Magenta 100% Yellow 100%
%Clay75/AP25 325 kN/m Clay100/AP0 325 kN/mClay75/AP25 440 kN/m Clay100/AP0 440kN/m
• improves printed gloss for all sub-colours with AP pigment• improved color strength with lower amount of printing colour
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Surface StrengthInitial Pick Velocity
0
2
4
6
8
10
12
14
16
18
Clay75/AP25 325 kN/m
Clay100/AP0 325 kN/m
Clay75/AP25 440 kN/m
Clay100/AP0 440kN/m
m/s
• better pick resistance, better surface strength even withlow calendering pressures with AP addition
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Adhesion Promotion
Clay 100 % 75 % Clay25 % AP
- improved surface properties (gloss, smoothness, brightness)
- improved surface strength - improved offset printability (print gloss and density)→ adhesion promotion as coated surface in extrusion
coating
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ProductsNanoparticles or nanoporous structures or foams based onacetylated starch with varying molecular weight and substitution degree. Preparation in pilot scale.
Properties- Mathematical models show that optimum light scattering
with spherical starch pigment morphology particles is obtained with particle diameters between 250-400 nm.
- Low packaging density (0,35) gives better light scattering than high (0,6).
- Non-mineral spherical pigments in coating give good:- improved surface properties (gloss, smoothness, brightness,
surface strength) - improved offset printability (print gloss and density)
- adhesion promotion as coated surface in extrusion coating
Conclusion
1000 nm 1000 nm 2000 nm
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Acknowledges
VTT - Technical Research Centre of FinlandJuha Saari, Kirsi Kataja, Pia Qvintus-Leino, Lauri Kuutti, Soili Peltonen, Hannu MikkonenWestern Michigan UniversityMargaret Joyce
University of HelsinkiProf. Kari Lumme and Dr. Antti PenttiläUniversity of JoensuuProf. Raimo Silvennoinen, Petri Karvonen and Antti OksmanGeological Survey of FinlandDr. Saija Luukkanen, Mauno Miettinen
Funding: Tekes VTTM Real Oyj Ciba Specialty Chemicals OyStora Enso Oyj Metso Paper Oyj
