Commercial Manufacture and Application of Micro-Fibrillated Cellulose in Paper and Paperboard Per Svending, Imerys Mineral AB, Sweden September 17th 2015 Specialty Papers Conference Milwaukee WI, USA

Publicised images of ”cellulose nanofibrils” show great diversity A wide range of shapes and sizes made through different processes by companies, universities, and institutes across the world.

FiberLean MFC and filler FiberLean™ microfibrillated cellulose (MFC), a recent addition to the papermakers toolbox Surface micrograph of finepaper containing FiberLean MFC and filler

The FiberLean™ MFC process Co-grinding pulp to MFC in the presence of minerals. The mineral acts as a very fine grinding media Robust and reliable equipment of relevant industrial scale. On-site manufacturing, using a minor side stream of mill pulp. No pre-treatment of fiber required. The FiberLean product is a MFC/mineral composite.

Co-grinding pulp to MFC in the presence of mineral Relatively coarse fibrils. Fibril length is important for wet end addition A wide range of pulps can be used Also flexible with regard to the mineral GCC PCC Kaolin Talc TiO2 1 μm

Commercial scale experience with FiberLean™ MFC Packaging Coated Woodfree Specialty + mechanical Uncoated Woodfree Close to 50 full scale trials on 21 paper machines to date In Europé, North America, South America and Asia. Trials ranging from a few hours to several days. Extensive experience across segments 6 mills in UWF 6 mills in speciality and mechanical paper 8 mills in CWF 2 mills in Packaging 3 commercial contracts for on-site MFC plants.

Impact of MFC on paper strength Tensile Burst Bond Tear It is possible to increase filler by 10% or more and suffer no strength loss. Lab study Mesmer recirculating hand sheets (12 sheets) 70% Eucalyptus, 30% NBSK, 550 CSF Intracarb 60 filler

Impact of MFC on paper tensile Tensile Elongation TEA Modulus Lab study Mesmer recirculating hand sheets (12 sheets) 70% Eucalyptus, 30% NBSK, 550 CSF Intracarb 60 filler

Behaviour of MFC in the tensile stress-strain curve Pilot study 80% Eucalyptus, 20% NBSK, 500 CSF Intracarb 60 filler

Behaviour of MFC in the tensile stress-strain curve + 0,6 %-units of stretch + 21% Pilot study 80% Eucalyptus, 20% NBSK, 500 CSF Intracarb 60 filler

Impact of MFC on paper tensile Tensile Elongation TEA Modulus Lab study Mesmer recirculating hand sheets (12 sheets) 70% Eucalyptus, 30% NBSK, 550 CSF Intracarb 60 filler

Impact of MFC on optical properties Brightness Opacity Scattering Absorption Lab study Mesmer recirculating hand sheets (12 sheets) 70% Eucalyptus, 30% NBSK, 550 CSF Intracarb 60 filler

Impact of MFC on other properties Porosity Density Initial drainage The porosity impact can be important for hold-out of ink or coating colour. Density can be regained by trading the positive impact on smoothness and bond strength with less intense calendering and/or use of coarser fiber, such as CTMP. While initial drainage slows down there is a positive impact on couch and press solids. Lab study Mesmer recirculating hand sheets (12 sheets) 70% Eucalyptus, 30% NBSK, 550 CSF Intracarb 60 filler

FiberLeanTM performance summary Date Title of the presentation

Full scale results from adding FiberLean to increase filler level in a woodfree paper 2% MFC +8% filler 4% MFC +16% filler The strength of the paper is maintained at increasing levels of filler and MFC.

Based on porosity reduction Beyond the primary target application of filler increase in P&W papers there are new product development opportunities to pursue Based on porosity reduction Improved hold-out of coatings Based on strength and opacity De-materialisation

Reduction in coat weight to reach a given gloss level

Adding FiberLean™ MFC to specialty paper at constant filler loading all chemical pulp at 250 CSF and 20% filler To facilitate applications like this FiberLean can be supplied at up to 50% MFC content with the balance being almost any type of mineral filler.

Selecting correct filler loading to reach a given opacity and strength at minimum basis weight No filler - minimum sheet weight for required opacity Basis weight (g/m2) Target strength and opacity No filler - minimum sheet weight for required strength No filler - minimum sheet weight for required opacity Filler content (%)

Selecting correct filler loading and sheet weight with FiberLean™ Pilot paper machine data

Selecting correct filler loading and sheet weight with FiberLean™ Pilot paper machine data Constant opacity

Selecting correct filler loading and sheet weight with FiberLean™ Pilot paper machine data Constant opacity Constant strength

Selecting correct filler loading and sheet weight with FiberLean™ Pilot paper machine data Paper with no MFC 63 g/m2 8% filler 84% opacity 1,5 kN/m tensile 58 g/m2 Fiber Paper with 2% MFC 53 g/m2 17% filler 84% opacity 1,5 kN/m tensile 44 g/m2 Fiber Paper with 4% MFC 48 g/m2 21% filler 84% opacity 1,5 kN/m tensile 38 g/m2 Fiber

Summary and conclusions MFC is now available for commercial use in papermaking Filler increase in P&W paper is a key application Several product development projects for packaging and specialty papers are ongoing Using MFC and filler to tailor a paper grade to required opacity and strength targets with minimum material use offers one of the most exciting opportunities.

Acknowledgements To my colleagues at Imerys FiberLean R&D in Par Moor Centre in the UK who have done most of the test work, and especially to Dr Jon Phipps, who designed and ran the constant opacity/strength experiments.

Thank you! Source: Peter Callesen, www.petercallesen.com