Aqueous Nanocomposite Barrier Coatings – A more sustainable option for high barrier
flexible packaging
Harris A. Goldberg; Carrie A. Feeney, and Michele Farrell InMat® Inc.
216 Route 206 Suite 7 Hillsborough, NJ 08844
Phone: 908-874-7788 & Fax: 908-874-7672 Email: [email protected]
•InMat History •Technology Platform and Approach •Oxygen Barrier Performance •Moisture Barrier Performance •Laminate Barrier Performance •Screening Results for Retort •Summary and value proposition
Outline
Elastomeric Coatings High Barrier Coatings
High Solid Paper Coatings
• Chemical protection • Flexible packaging • Barrier paperboard for food and juice cartons
• Sports balls • Rigid packaging • Grease resistant paper
• Specialty industrial • Medical devices
• Tires
Air D-Fense™ 2000
Nanolok™ PT ADV Nanolok™ PT E Nanolok™ EXC
Nanolok™ PT MM Nanolok™ WR
Nanolok™ PT HSC
InMat Inc. Leader in water based, environmentally friendly high barrier clay-polymer nanocomposite coatings Product platform with commercial success & easily scaled to large volumes Current product lines use four different polymers and clays One component formulations that can be applied using standard coating methods (roll, spray or dip)
• Reduced material costs • Environmentally friendly / all ingredients have FDA food packaging status • Polymer can be chosen to meet the requirements of the market • Large (1-5 orders of magnitude) improvements in barrier properties over unfilled polymer • Fundamentally different approach to clay–polymer nanocomposites
Substrate
Nanocomposite Barrier
Aqueous Nanodispersed
Suspension Once dry a thin coating provides extremely high barrier
Nanocomposite Barrier Coating Platform: Coating formulations using nanoclay & polymer dispersed in water
Clay – Polymer Nanocomposite Barrier: Basic Concepts
• Use clay minerals which are easily exfoliated in water to form 1-3 nm thick silicate sheets
• Impermeable sheets form tortuous path increasing barrier properties of polymer
• As concentration increases, a large fraction of the polymer will be near a clay surface
• May cause significant changes in permeability of polymer
Key Variables • Polymer permeability • Plate aspect ratio • Clay concentration • Dispersion and microstructure • Orientation
LCP
NylonPET
LDPEPP
PVDC EVOH
NanolokTM PT
PANMXD-6
PLA
EVOH
0.0001
0.001
0.01
0.1
1
10
100
1000
0.001 0.01 0.1 1 10
Water Vapor Transmission (gm-mm/m2-day)
O2 p
erm
eabi
lity
(cc-
mm
/m2 -d
ay)
Most
Least
Nanocomposite Barrier Coatings Provide High Barrier in a Water-based, Environmentally Friendly,
Coating Formulation
Optical Interference Image provides Surface Topography Map
• Flexible film: • Many roll coating processes
will work » Examples: Slot dye, curtain,
flexo, and gravure
• We have used reverse offset gravure
– Enables simple thickness control by changing relative speed of film and gravure cylinder
Application Processes: Many can be used to coat films
Gravure roll
Offset roll
Film
MVTR
Top Bottom Top Bottom DOG Coat weigh Thickness 25.91 5.24 60 1.36 0.91
8.2 0.65?? 50 1.24 0.88.1 0.9 40 1.06 0.597.7 1.0 30 0.88 0.459.3 0.8 20 0.71 0.35
10.1 0.9 10 0.2913.2 1.7 5 0.1521.0 2.67.5
56.011.8 1.312.9 2.615.1 1.3
21C, 56% RH38.5, (85% RH)
0
0.4
0.8
1.2
1.6
0 20 40 60 80DOG %
PT ADV-3, PET 92g
Coat weight (gm/m2)
Thickness (µ)
gsm
Thickness
Correlation: Differential offset gravure versus coat weight (gsm)
There is a good correlation between the % offset, the coat weight (gsm) and the measured coating thickness.
Effect of Relative Humidity on Packaging Barrier Coatings
0
5
10
15
20
25
30
35
40
45
50
0% 50% 65% 80%
Oxy
gen
Perm
eabi
lity
(cc
um/m
2 da
y at
m)
Relative Humidity
PTADV-7
WR301409
PVDC
EVAL E
EVAL F
EVAL E
PVDC
EVAL F WR
PTADV
Nanolok coatings <1 micron thick will replace several microns of competitive materials.
290
47
7
50
14
2.9
47
14
2.4
1
10
100
1000
PLA 80g PET 48g BOPP 80g
MVT
R (g
m/m
2 .day
) Control
Coated Films
2-Level Model
Coating thickness: ~ 0.7 µ
InMat barrier coatings also provide large improvements in moisture barrier.
Nanolok PT™
0.3 mil Adhesives
Current Technology Total thickness: ~2.6 mils
0.5 mil PET
1 mil PE
InMat Technology Total thickness: ~1.8 mils
0.5 mil PET
0.5 mil EVOH
1 mil PE
0.05 mil Nanolok
Flex Packaging Example Fewer layers in the final package results in cost reduction.
Substrate film
Barrier coating Barrier coating thickness
Adhesive Adhesive thickness
Laminating film Lamination conditions
• Temperature • Pressure • Time (rate)
PET
PE
barrier adhesive
BOPP
BOPP barrier
adhesive
Performance of Flexible Laminates There are a large number of critical variables.
x
x
x
x
Effect of Lamination Oxygen transmission rate reduced by a surprising amount.
•Large reductions in OTR after lamination occur on almost all samples – PET, BOPP and variations in adhesives. •The reductions are more pronounce for thinner coatings that contain more defects.
150 150 150
200 200220 220
15 15 23 25 20 30 250
50
100
150
200
250
3 5 11 5 11 5 11
OTR
(cc/
m2
day
atm
)
Adhesive thickness (gsm)
Thin Coatings of Nanolok WR 301409Vary BOPP substrate & Adhesive Thickness
(BOPP/WR-S/Toyo Adh/BOPP)
control
laminate
BOPP 17 um
BOPP 57 umBOPP 20 um
Barrier coating thickness estimated to be ~ 0.2 microns
Peel Strength: Barrier coating thickness & adhesive coat weight are both important.
•High adhesive coat weights decrease peel strength on the thin barrier coatings.
190
60 45
170140
40
210240 250
0
50
100
150
200
250
300
3 gsm 5 gsm 11 gsm
Peel
Stre
ngth
(g/i
nch)
Effect of Coating Thickness & WATER based Adhesive Thickness on Peel Strength
Using Nanolok WR 301409 and BOPP 57 um substrate(BOPP/WR-S/Liofol/BOPP)
0.2 micron
0.45 micron
0.7 micron
Feasibility for Retort Packaging Recent laboratory simulation demonstrated!
1 µm Nanolok
5 µm Adhesive lamination
2 mil BOPP
2 mil BOPP
2 mil BOPP
2 mil BOPP
2 mil BOPP
Coated Film (Reverse gravure roll
coated)
Lab Lamination (with solvent adhesive)
Simulated Retort (Boiling water, 1 hr)
Barrier (cc/m2 day atm) 2 0.3 1
Clarity Good Excellent Excellent
Adhesion n/a Good Good
Boiling water, 1 hr
OTR of uncoated 2 mil BOPP ~1300cc/m2-day atm
Laminate Performance
•Thinner barrier coatings can be used in laminates due to the improvements in OTR after lamination. •OTR not degraded after boiling in water for 1 hour. •Peel strengths limited by cohesive strength. •Large variation in cohesive strength of laminate depending upon:
•Barrier coating thickness •Adhesive coat weight •Substrate & surface treatment •Type of adhesive
•It is likely that the laminating adhesive and/or the laminating process is reducing the peel strength – further work is needed.
Product Permeability1 (cc um/m2 day atm) MVTR2 Adhesion
0% RH 65% RH 80% RH
PT ADV-7 0.3 0.5 3 ++ +
PT ADV E 1.6 3.1 8.8 + +
EXC 1007V 0.1 3.5 39
WR 301409 0.4 0.6 15 + ++PET,PP,PLA
InMat Product Line: Several high barrier coatings available for flex packaging
applications
•All coatings can be applied directly to corona treated films without primer • Coatings can be used in laminated and/or top coated structures • Coatings can be used as base coat for ink, or as overcoat
Barrier material cost savings
• Reduce number of layers as Nanolok™ barrier can usually be applied directly to packaging film without an adhesive
Reduced package weight – source reductions and disposal costs
• Standard application equipment for film • Low cost spray equipment for rigid parts • No solvents or hazardous materials
Water based coatings with neutral pH
Potential integration into printing and/or lamination process
High oxygen barrier performance along with significant moisture barrier improvements.
Potential for retortable and steam sterilized packaging
Value Proposition Summary
InMat has a line of unique, water based, barrier coatings suitable for flexible packaging and is seeking
partners for full commercialization.
