Post on 31-Jan-2018
transcript
A Comparison of Aqueous Primers for Anchoring Vacuum Deposited Aluminum to Film Substrates
Ginger Cushing Business Manager Americas – Flexible Packaging AIMCAL Coating & Laminating Conference – Prague 2012
AGENDA
• Introduction • Objective of the Study • Experimental
– Materials – Trial
• Results/Discussion • Conclusion
Vacuum Deposition of Aluminum on Film Substrates • Substrate Preparation
– Smoothness • Adhesion to Film (BOPP and BOPET)
– Oxidative or chemical plasma – Coextruded skins – Chemical Primers
Objective of the Study
Develop a chemical primer that will: 1. Adhere well to treated film without a
separate adhesion promoter 2. Produce a smooth surface 3. Adhere well to metal 4. Yield a bright metalized film with good
Oxygen barrier
Materials • Uncoated film substrates
– 12µ BOPET – 20µ BOPP
• Barrier Primer A – 10% solids in water
• Barrier Primer B – 10% solids in water
• Aluminum for metalizing
“Banded” Cylinder
5.0 BCM5.7 BCM6.6 BCM6.9 BCM7.3 BCM9.2 BCM4.3 BCM
68.00"8.50"
0.50"
62.50"44.50"26.50"
8.50"2.75"
Volume (cc/m2) Measured Coat Weight (gsm)
11.3 0.5 10.7 0.47 10.2 0.45 8.8 0.39 7.8 0.34
Cell delivery 45%
Oxygen Transmission Rate
• Mocon Ox-Tran 2/21 • Unsupported film • 0% RH, 23oC • Average of 2 samples, each cycled 5
times
OTR at 0% RH for Primers A and B on 12u BOPET (no metalizing)
00.10.20.30.40.50.60.70.80.9
0.5 0.47 0.45 0.39 0.34
Oxy
gen
Bar
rier,
cc/m
2/da
y/at
m
Primer Weight, dry g/m2
AB
Average dry OTR on 12u BOPET across banded cylinder • 0.43 dry g/m2 primer coat weight • Primer A = 0.574 cc/m2/day/atm • Primer B = 0.380 cc/m2/day/atm
Method • Gravure coat 0.2 dry g/m2 of each coating to film
– Corona treat film prior to priming – Use smoothing bar – Dry thoroughly with hot air – Rewind
• Splice all the rolls together • Vacuum metalize the primed substrates to an
optical density of 2.0
Adhesion Tests
• Adhesion of coating to base film prior to metalizing by 3M 610 Scotch Tape
• Adhesion of metal to coated substrate by modified AIMCAL TP105
Silicone paper
EVA Coated PET Film
Test film (metal up)
Scotch 610 tape
Silicone paper
Adhesion Test Results
• Scotch Tape did not remove any coating from the substrate.
• Metal adhesion very strong, between 600 and 710 g/25mm
Film/0.2 gsm Primer/2.0 OD Metallizing OTR @ 0% RH
3.76 0.53
140
6.56 7.1
547
0
100
200
300
400
500
600
Primer A Primer B Plain Film
Oxy
gen
Bar
rier,
cc/m
2/da
y/at
m
12u BOPET20u BOPP
Next Steps
• Laminations of film-barrier primer-met/solventless adhesive/film barrier testing under way
• Elevated humidity testing in progress
Summary – Clear BOPET Film • Both primers exhibited excellent film
adhesion • Coating was clear and even. • Primer B was better than A.
Summary – Metalized Film • Metal adhesion excellent • Metal brightness excellent • Primer A barrier close to Primer B on
BOPP • Primer B out-performed Primer A in OTR
testing on BOPET
Discussion
• BOPET/0.4 gsm primer = 0.38 cc/m2/day/atm
• BOPET/0.2 gsm primer/2.0 met = 0.53 cc/m2/day/atm
• Why?