Mineral/ microfibrillated cellulose composite materials:

Mineral/ microfibrillated cellulose composite materials:

High performance products, applications and product forms

David Skuse, Mark Windebank, Tafadzwa Motsi and Guillaume Tellier

Presented by:

David Skuse
VP Technology
FiberLean Technologies Limited

Outline

  • Introduction
  • New mineral/ MFC composite products
  • Comparison of mineral/ MFC composites with other MFCs
  • Mineral/ MFC composite product forms
  • Performance of high solids mineral/ MFC composite product forms
  • Conclusions

Introduction

  • MFC use has been limited by high process energy requirement and equipment complexity
  • Cost effective grinding-based method for the production of mineral/ MFC from minerals and cellulose pulp (TAPPI Nano 2014, 2015, 2016, 2017)
    • Cellulose fibres are co-processed with mineral particles. The mineral particles act a micro-grinding media, thus, reducing the energy requirement
    • The process can be accomplished using robust, industrially proven grinding equipment
  • We have been able to produce mineral/ MFC composites with a wide range of pulps and minerals (TAPPI Nano 2016)
  • FDA FCN for food contact paperboard
  • 8000 dry metric tonnes pa of fibril capacity (40 000 dry metric tonnes of mineral/ MFC composite) installed across three continents. Further capacity under construction

Product characterisation and test methods 1

  • Processsing and handling of mineral/ MFC composites are dominated by the high viscosity of MFC arising from presence of high surface area hydrophillic fibrils. Typical fibre solids is ~2%
(a) (b)
photograph of mineral MFC composite micrograph of mineral MFC composite

Photograph (a) and micrograph (b) of mineral/ MFC composite
showing the high viscosity and fibrillar structure

Performance observations

Typically, use of mineral/ MFC composites with a concomitant filler increase is associated with:

  • Performance observationsExcellent performance stability
  • Increased initial wet web strength
  • Minimal impact on wet end chemistry
  • Overall positive impact on drainage
  • Improved dry mechanical properties
  • Improved opacity
  • A much tighter sheet (reduced porosity)
  • Improved coating hold out
  • Improved smoothness
  • Maintaining bulk when fibre is replaced by higher specific gravity filler is a challenge but can be managed

Performance observations: Wood free filler top-up

Performance observations: Wood free filer top-upMineral/ MFC composites can be used to increase filler loadings in wood free sheets

  • Graph shows data from 16 full scale machine trials in wood free applications
  • Typically achieve approximately 10 part filler increase with a 2% MFC dose
  • There are new product development opportunities. SEMs show conventional 17% GCC filled sheet (left) and a 55% GCC filled sheet with 4.5% MFC dose (right) from a pilot study

Product characterisation and test methods 2

  • Product characterisation is straightforward; solids, percent of solids that is fibre, viscosity and in-house tensile test

Product characterisation

In-house tensile test and handsheet data show good correlation for a range of mineral/ MFC composites samples prepared with varying processing conditions

Running full-scale trials with low solids products

  • Running full-scale paper machine trials with MFC difficult due to low solids, viscous product
  • Our solution was to build a production plant producing a dewatered crumble product
  • Approximately 80 full-scale paper machine trials to date
Mineral/ MFC composite filter cake product form Mineral MFC composite production plant in the UK
Mineral/ MFC composite filter
cake product form

Mineral/ MFC composite production plant in
the UK, 2000 dry metric tonnes pa of
fibril capacity.
Operational since Q4 2013

Product forms for trials

Bottles and barrels, Transitanks, Trucks and ISO tanks

  • Slurry
    • Bottles and barrels, Transitanks, Trucks and ISO tanks
  • Filter cake
    • Buckets, barrels, big bags

 

 

Bottles and barrels, Transitanks, Trucks and ISO tanks Bottles and barrels, Transitanks, Trucks and ISO tanks

Product forms for trials

  • Slurry (~2% MFC fibre solids)
  • Bottles and barrels, Transitanks, Trucks and ISO tanks

Product forms for trials

Product forms for trials

  • Product forms for trialsFilter cake (~10-15% NFC fibre solids)
  • Buckets, barrels, big bags

Filter cake
Bag weight ~ 1000 kg (~2200 lb) = 150 kg (~330 lb) dry MFC

Largest shipments to date
292 bags = ~44 tonnes (~48 short tons) of dry MFC

New product health and safety assurance

  • Cleared through Environment Canada, Health Canada, US EPA and US FDA (FCN 1582, for 5 wt.% fibrils in packaging board)
  • BfR application filed for consideration under recommendations XXXVI, XXXVI/1, XXXVI/2, and XXXVI/3

Mineral/ MFC composites with a range of fibres

Mineral/ MFC composites with a range of fibres

It is possible to prepare effective mineral/ MFC composites from a wide range of fibres

Mineral/ MFC composites with a range of minerals

Mineral/ MFC composites with a range of minerals

Scanning electron micrographs of mineral/ MFC composites samples prepared with a range of different minerals (80:20, mineral/ NBSK, mineral/ MFC composite)

 

It is possible to prepare effective mineral/ MFC composites from a wide range of minerals

New mineral/ MFC composite products 1

  • There have been improvements in product tensile and viscosity peformance since the initial launch in 2014

New mineral/ MFC composite products 1

Tensile and viscosity performance of a series of laboratory and pilot scale prototype mineral/ MFC composite products (80:20, mineral/ MFC composite)

New mineral/ MFC composite products 2

  • Improvements in mineral/ MFC composite tensile properties translate to improved sheet properties allowing improved products or dose reductions

New mineral/ MFC composite products 2

Paper sheet burst index at 20 wt.% filler content versus MFC content for two mineral/ MFC composite product prototypes

Comparison of mineral/ MFC composites with other MFCs

  • Mineral/ MFC composites give at least equivalent performance to that obtained with other MFCs

Comparison of mineral/ MFC composites with other MFCs

Paper breaking energy versus mineral filler content for two mineral/ MFC composite products and other MFCs

Mineral/ MFC composite product forms

  • A high solids MFC product form is highly desirable since it allows merchant sales
  • It is easy to dry MFC but the challenge is redispersion in water at customer location
50% NBSK, 50% GCC composite

50% NBSK, 50% GCC composite

 

 

Mineral/ MFC composites can be dried to high solids and then redispersed in water with low energy input and the original properties restored

High solids mineral/ MFC composite product forms

High solids mineral/ MFC composite product forms

High solids mineral/ MFC composite product form ((50:50, 60%<2um GCC/ NBSK mineral/ MFC composite, 51% solids))

High solids mineral/ MFC composite product forms: Product stability

Mineral/ MFC composites display performance stability

Mineral/ MFC composites display performance stability for > 150 days when stored in intermediate bulk containers under ambient conditions

Performance of high solids mineral/ MFC composite product forms: Paper and board applications

Mechanical properties of sheets containing let-down high solids mineral/ MFCMechanical properties of sheets containing let-down high solids mineral/ MFC are equivalent to controls

Conclusions

  • Mineral/ MFC composites are produced using a cost-effective, robust process and have proven full-scale availability
  • Mineral/ MFC composites can be produced using a wide range of minerals and pulps
  • The tensile and viscosity behaviours of mineral/ MFC composites have improved since the intial product launch in 2014
  • Mineral/ MFC composites give at least equivalent behaviour to other MFCs in paper and board applications
  • High solids mineral/ MFC composite product forms can be fully re-dispersed to their original properties and allow the operation of merchant plants
  • We believe that mineral/ MFC composites are an important additive for paper and packaging applications