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Mechanical investigations of ultrathin coatings on polymer films - towards prediction of permeability properties Dr Jessica Bolinsson
Mechanical investigations of ultrathin coatings on polymer films -towards prediction of permeability propertiesDr Jessica Bolinsson
General
Acknowledgement
Academic research project in collaboration with Uppsala University:Prof. Kristofer GamstedtMarcus Tavares da Costa (PhD student)-> done the work!
Tetra Pak:Eskil AndreassonPierre Fayet (Adhemon Sarl)Christian Neagu (former at Tetra Pak)
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General
Division of Applied Mechanics
E. Kristofer Gamstedt,
PhDProfessor and head of division
of Applied Mechanics
Marcus TavaresPhD candidate in Solid Mechanics
Mechanics of coatings project
Ångström Laboratory
S:t Lägerhyddsv. 1, Box 534, 751 21, Uppsala, Sweden
Tel: 018-471 3026
e-post: [email protected]
Webpage:http://www.teknik.uu/applmech
1. Comparison of test methods estimating thestiffness of ultrathin coatings, J. Coat. Technol.Res. 15 (2018) 743–752.
2. Experimental assessment of micromechanicalmodels for fragmentation analysis of thin metaloxide coatings on polymer films under uniaxialtensile deformation, Surface and CoatingsTechnology. 370 (2019) 374–383.
3.Transverse ridge cracking in tensile fragmentationtests of thin brittle coatings on polymer substrates,Surface and Coatings Technology. (2019)
Laboratory Equipment(More information on www.teknik.uu/applmech )
Shimadzu AGS-X tensile tester
X-ray micro-computedtomography
Aramis 3D from GOM
In-situ mechanical testing in SEMTo be presented up next
Ultramicrotomefor nanosectioning
Industrial collaboration
• Tetra Pak • SCA AB• DS Smith Packaging plc • ABB Corporate Research• Innventia AB• Sandvik AB• Others
General
Outline
► Tetra Pak in short, what do we do
► Motivation
► Experimental/Methods and results
► Summary
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AIMCAL 2019
We commit to making food safe and available, everywhere
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OURPROMISE
OUR VISION
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SustainabilityAutomationServices Packaging
Food ProtectionDistribution
Marketing
What does Tetra Pak do?
Consultancy Processing
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• Processing equipment (dairy, cheese, beverages etc)
• Packaging equipment and packaging material (liquid food)
• Services (maintenance, training, installation etc)
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65 years working alongside food producersOur Business
24.100Employees
>175Countries
€11.4 billion Net sales
Units delivered
Units in operation
Packaging Processing Downstream
336 2 230 938
8 860 76 000 20 000
>3% of turnoverInvestment in R&D
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General
The widest range of shapes and volumes to choose fromOur carton family portfolio
Tetra Classic®
Aseptic
Tetra Fino® Aseptic
Tetra Gemina® Aseptic
Tetra Rex®
Tetra Prisma® Aseptic
Tetra Brik®
Aseptic Slim Leaf
Tetra Brik® Aseptic Base Crystal
Tetra Wedge®
Aseptic
Tetra Recart®
Tetra Top®Tetra Brik®
Aseptic Edge
Tetra Top® MiniV
Tetra Brik®
Aseptic
Tetra Evero®
Aseptic
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AIMCAL 2019
General
Do you know...?
► How many billion liters of packed food that are consumed in the world every day?
4,7 billion liters – 35% of total consumption
► How many Tetra Pak packages have been consumed last year?
25 per every person on the planet, 188 billion packs
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http://tetrapak.com/AIMCAL 2019
General
Ultra thin coatings (< 100 nm)+
Polymer substrate
Oxygen barrier Light barrier
Barrier properties
Motivation – barrier solution for liquid food packages
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General
Oxygen- and Water Vapor Barrier demands
Food demands
Ref: M Schmid, K Dallmann, E Bugnicourt, D Cordoni, F Wild, A Lazzeri, K Noller: ”Properties of Whey-Protein-Coated Films and Laminates as Novel Recyclable Food Packaging Materials with Excellent Barrier Properties” International Journal of Polymer Science, Volume 2012 AIMCAL 2019
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General
Product and package simulation capabilities
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What’s important for juice/milk?
Incident lightTransmitted and absorbed light
Ambient oxygen
Permeated and dissolved oxygen
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JuiceDissolved oxygen level is key for the consumption of vitamin C. Package OTR and temperature in turn is vital for dissolved O2 level.
MilkDissolved oxygen level and presence of light is key for the consumption of fatty acids and amino acids, which produce taste deviations. Package OTR and light transmission and temperature in turn is vital for dissolved O2 level and absorbed light.
O2
Surface reactions +
Amino acids, fatty acids
Bulk reactions
+Ascorbic acid
+
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Modelling generate large savings of cost & time in packaging material development!
Virt
ualt
estin
gPh
ysic
alte
stin
g
Package OTR models Vitamin C decay models
Converting, Filling & Testing Storage trials
PM & Package OTR Product shelflife
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Material Mechanics
Material properties
Damage mechanisms
Virtual Predictions
Macroscopic mechanicalmaterial response
Microscopic response:Combine micro mechanics
with macro package
simulations
Create virtual material descriptionsof
the material mechanics
Extract and create damage models representing the fragmentation process
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Fracture behavior under tension
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No cracks
The crack onsetstrain, COS
The crack density increases linearly
The crack density at saturation, CDsat
Yanaka, Thin Solid Films, 2000 AIMCAL 2019
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Schematic of the current approach:
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1. Fragmentation test
2. Micromechanical modelfor
The coating strength 𝝈𝝈 and adhesion strength 𝝉𝝉
3. Interface material property:G, the fracture energy
(crack resistance)
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Samples used for fragmentation tests:
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Barrier coating Thickness[nm] Substrate Manufacture
ProcessTiO2Al2O3
(MOX) 20
PET (100 µm thick) ALD TiO2 20
TiO2Al2O3(MOX) 4
TiO2 6
* E. Dickey, W.A. Barrow, High rate roll to roll atomic layer deposition, and its application tomoisture barriers on polymer films, J. Vac. Sci. Technol. A. 30 (2012)
Barrier coating deposited by ALD in roll-to-roll*
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Fragmentation tests: Tensile stage inside an SEM
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SEM (TM-1000) Deben microtest stage
Tavares da Costa et al, Surf. & Coat. Tech. 370, 374-383, 2019 AIMCAL 2019
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30 µm
Fragmentation tests:• Crack Density versus strain• Up to 40% tensile strain• Displacement rate of 0,1mmm/min
Tavares da Costa et al, Surf. & Coat. Tech. 370, 374-383, 2019 AIMCAL 2019
General
Digital image processing using MATLAB(Ongoing)
a) Original Picture b) Peaks
c) Count
Fragmentation tests:
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Results – fragmentation tests
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Barrier coating Thickness[nm] Substrate Manufacture Process
TiO2Al2O3 (MOX) 20
PET (100 µm thick) ALD
TiO2 20
TiO2Al2O3(MOX) 4
TiO2 6
AIMCAL 2019Tavares da Costa et al, Surf. & Coat. Tech. 370, 374-383, 2019
General
CD vs Strain
Probability of failure
Cohesive coating strength
Interfacialshear
strength
(Weibull,1939)
(Hui et al., Composites Science and Technology, 1998)
(J. Andersons et al., Mechanics ofComposite Materials,1995)
Mircomechanical modelling - schematic
AIMCAL 2019Tavares da Costa et al, Surf. & Coat. Tech. 370, 374-383, 2019
General
Coating Substrateh
[nm]
Micromechanical Model
𝜏𝜏[MPa]
𝜎𝜎[GPa]
TiO2
PET
20 120 4.9MOX 20 101 2.5TiO2 6 84 4.8MOX 4 22 1.4
Micromechanical modelling - results
Hui et al., Composites Science and Technology, 1998)
AIMCAL 2019Tavares da Costa et al, Surf. & Coat. Tech. 370, 374-383, 2019
General
Results – Analysis of ridge cracking
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Use ridge cracks in model for fracture energy 𝑮𝑮𝒊𝒊
M.D. Thouless, Combined Buckling and Cracking of Films, J. Am. Ceram. Soc. 76 (1993) AIMCAL 2019Tavares da Costa et al, submitted to Surf.Coat.Tech.
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Add analysis of strain field of substrate using DIC
AIMCAL 2019Tavares da Costa et al, submitted to Surf.Coat.Tech.
Equipment:DIC GOM Aramis stereo systemShimadzu Autograph AGS-X
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Results – Fracture energy at delamination 𝑮𝑮𝒊𝒊
AIMCAL 2019Tavares da Costa et al, submitted to Surf.Coat.Tech.
Equ. 5:
General
Summary
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SEM + tensile stage, digital image processing, nm-thin brittle coatings
CD versus strain, add micromechanical modelling
• Cohesive coating strength 𝝈𝝈• Interfacial (shear) strength 𝝉𝝉
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Summary
• Fracture energy at delamination, 𝑮𝑮𝒊𝒊
• FE simulation in agreement
Closing in on full simulation/prediction of barrier properties! To be continued….
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