Rheology of high solids Microfibrillated cellulose and miner al suspensions at high shear rates

Lead Research Organisation: University of Birmingham
Department Name: Chemical Engineering

Abstract

Microfibrillated cellulose (MFC) is a wood pulp material where the fibril bundles are partially separated from each other, giving a high surface area product that attracts great interest as a sustainable reinforcing material. FiberLean Technologies Ltd has developed a novel, reliable, and scalable process to produce MFC by grinding a variety of cellulose species in water with a range of different mineral types; this product is an MFC- mineral composite material known as FiberLean.
With the decline in printing and writing paper grades, many paper mills are looking to convert their graphic paper machines to produce liner board or other packaging products. White printable top layers for packaging and other paper grades are conventionally produced as a seperate sheet before being couched, pressed, and dried together with the base layer. As a consequence, manufacturing these two-ply papers requires the additional construction of a complete paper machine wet-end section that is a major rebuilt and investment. The top layer of these multilayer grades typically comprises of a lightly refined hardwood Kraft fibre with 10%- 20% filler with the main objective of this layer being to optically cover tha base layer and achieve a high brightness surface suitable for printing. A solution to this costly papermachine upgrade is to apply a low weight FiberLean coating at low solids content (7.5%-10%) directly on the still consolidating base layer at the wet-end section of a paper machine using a coating applicator positioned above the wire. The mineral content of this novel coating can be as high as 80% mineral with the MFC acting as a binder holding the white layer from penetrating into the low solids content base. The two layers can then be pressed and dried simultaneously using the existing paper machine components upgrading single layer paper machines to two ply printable paper grades with a substantially lower cost investment.
By optimising this methodology of applying an even FiberLean ply at the wet-end of a paper machine, the utilisation of the same principal can contribute in the development of new aqueous based sustainable barrier layers for packaging applications. These MFC based layers could be used as a pre-coat for moisture, gas and grease barrier coating applications by closing up the highly porous surface of the base paper and allowing an impovement in the barrier coating holdout. This could allow lighter barrier coatweights to be applied without compromising the target properties of the end product. Furthermore, the smooth, low porosity FiberLean ply can on its own act as a barrier for moisture and grease creating numerous possibilities for this application.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S023070/1 01/10/2019 31/03/2028
2296159 Studentship EP/S023070/1 04/11/2019 03/11/2023 Soultana Selina