Applications of FiberLean microfibrillated cellulose in and out of the paper industry

Applications of FiberLean microfibrillated cellulose in and out of the paper industry

Biopolymerkolloquium, Potsdam, 24th January 2019

Jonathan Phipps

FiberLean microfibrillated cellulose – what is it?

FiberLean microfibrillated cellulose 1

 

FiberLean microfibrillated cellulose 2

  • Simple wet media grinding process reduces cellulose paper pulp fibres to microfibrils
  • Product has fibrils and fibre fragments over a wide range of length scales
  • Fibres are mixed with micron-sized mineral particles to aid separation of fibrils

FiberLean microfibrillated cellulose – microstructure and properties

FiberLean microfibrillated cellulose microstructure 1 FiberLean microfibrillated cellulose microstructure 2
FiberLean microfibrillated cellulose microstructure
  • Finest microfibrils form networks around mineral particles
  • Very high surface area available for bonding and interaction
  • Entangled fibrils can generate high viscosity in suspension
  • Drying from water draws fibrils together to form strong bonds
  • Dried and bonded fibrils are resistant to wetting and dispersion

FiberLean production for paper applications

FiberLean microfibrillated cellulose production for paper applications

  • Satellite plant located at paper mill (3 operational)
  • Pulp received, processed and delivered at low solids (<4% cellulose in water)
  • Product fed direct to papermaking process (no dewatering or drying required)

Rheological properties of FiberLean Microfibrillated Cellulose

Rheological properties of FiberLean Microfibrillated Cellulose
  • Entangled fibril networks
  • High low-shear viscosity at low solid concentration (<2%)
  • High yield stress
  • Very shear-thinning – approaches water viscosity at > 104 s-1
  • Can be sprayed or jetted at high speed
Entangled fibril networks High low-shear viscosity at low solid concentration ( 104 s-1 Can be sprayed or jetted at high speed
Rheological properties of FiberLean Microfibrillated Cellulose Entangled fibril networks High low-shear viscosity at low solid concentration ( 104 s-1 Can be sprayed or jetted at high speed

FiberLean in Papermaking

Papermachine Schematic

Papermachine schematic

Paper structure, fillers and microfibrillated cellulose

Paper structure, fillers and microfibrallated cellulose

 

Paper structure, fillers and microfibrallated cellulose

Paper structure, fillers and microfibrallated cellulose

Optimisation of filler content

Optimisation of filler content

Property Changes with microfibrillated cellulose and filler increase

Property Changes with microfibrillated cellulose & filler increase

Paperboard grades

Paperboard grades - corrugated board

Corrugated board

Paperboard grades - white top

“White top”

Paperboard grades - folding boxboard

Folding boxboard

Paperboard grades - top former

  • Packaging grades are multilayer structures because they need to be resistant to bending
  • Filler is used only in the surface layers for optical and printing properties
  • Layers are formed individually and pressed together when wet – web is only placed in tension afterwards

Paperboard stiffness

Paperboard stiffness

  • Bending a sheet of material causes stretching of the outer surface and compression of the inner surface
  • At small deformations, resistance to stretching and compression must be equal

 

  • Resistance to bending – bending stiffness – is therefore directly related to the elastic modulus of the material
  • Modulus (E) = Force / (x-section area x strain)
  • For paper, x-section area depends on pressing and calendering, so instead we define tensile stiffness index (TSI): –
    TSI = Force/ (width x gsm x strain)
  • TSI is not very sensitive to pressing or calendering

 

Paperboard stiffnessFor a single layer, Bending stiffness = (E x thickness3 ) /12

= (TSI x gsm x thickness2) /12

Stiffness is very sensitive to thickness

FiberLean mfc in paperboard outer layer

FiberLean microfibrillated cellulose in paperboard outer layer

  • Addition of mfc allows filler increase and weight reduction without loss of tensile stiffness

FiberLean microfibrillated cellulose in boxboard – full scale example

Improved brightness, constant stiffness, lower cost

Full scale example of FiberLean mfc in boxboard

Coating FiberLean Microfibrillated Cellulose at the ‘wet end’

Alternative method for making white top paperboard

 

Coating FiberLean microfibrillated cellulose at the wet end Coating FiberLean microfibrillated cellulose at the wet end

 

Coating FiberLean Microfibrillated Cellulose at the ‘wet end’

Coating FiberLean microfibrillated cellulose at the wet end

Coating onto wet, rough base at 500 m/min

Coating FiberLean microfibrillated cellulose at the wet end

High quality print on low speed coated base

Coating FiberLean microfibrillated cellulose at the wet end

Coating from 500 m/min trial

Using FiberLean Microfibrillated Cellulose as a precoat for barrier coatings

  • Food packaging needs water and/or oxygen vapour barrier
  • Aim to replace laminated polyethylene layers with water-based latex barrier coatings
  • Recyclable, repulpable, reduction in plastic content
  • Current paperboard products are too rough to allow defect-free coatings
  • Microfibrillated cellulose applied by wet end technique provides enhanced smooth surface

Porosity and Barrier properties

Sample Details Base Paper Base Paper +
MFC Layer
Base Paper +
barrier coating
Base Paper +
MFC + barrier coating
Plastic Coated
Freezer Paper
Base Layer g/m2 32 32 32 32 Unknown
MFC Layer g/m2 0 9 0 9
Coating Layer g/m2 0 0 14 12
COBB (Water penetration) g/m2 50 58 46 1 0.8
Solvent resistance (1=lowest, 16=highest) g/m2 <1 16 3 16 16
Water Vapour Transmission (38C, 95% RH) g/m2
day -1
1031 992 351 23 45.4

Using Microfibrillated Cellulose as a thickener in decorative paint

Component Function Weight% in dry film
TiO2 White pigment 19%
Kaolin/talc Mineral extender 30%
CaCO3 Mineral extender 35%
PVA latex Binder 14%
HEC/MFC Thickener 0.75%
Others Additives 1.25%

Formulation

Pigment Volume Fraction 66%
Wt% solids 52%

 

Using MFC as a thickener in decorative paint

Using MFC as a thickener in decorative paint

Using MFC as a thickener in decorative paint

HEC (hydroxyethyl cellulose)

Using MFC as a thickener in decorative paint
Using MFC as a thickener in decorative paint

FiberLean MFC

Dry film properties with Microfibrillated Cellulose – illustrative example

Dry film properties with MFC – illustrative example

Spinning fibres from suspensions of FiberLean Microfibrillated Cellulose

  • Fibre Spinning by hand from syringe with hypodermic needle

 

Spinning fibres from suspensions of FiberLean Microfibrillated Cellulose

  • Narrow needles and low solids make stronger fibres – fibril alignment