16 Apr 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/ microfibrillated cellulose composite 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/ microfibrillated cellulose composite composite materials are dominated by the high viscosity of MFC arising from presence of high surface area hydrophillic fibrils. Typical fibre solids is ~2%
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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:
Excellent 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
Mineral/ 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
In-house tensile test and handsheet data show good correlation for a range of mineral/ microfibrillated cellulose composite material 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
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| Mineral/ MFC composite filter cake product form |
Mineral/ MFC composite production plant in |
Product forms for trials
- Slurry
- Bottles and barrels, Transitanks, Trucks and ISO tanks
- Filter cake
- Buckets, barrels, big bags
Product forms for trials
- Slurry (~2% MFC fibre solids)
- Bottles and barrels, Transitanks, Trucks and ISO tanks
Product forms for trials
Filter 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/ microfibrillated cellulose composite materials 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
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
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
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
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
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 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 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/ 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