High Performance Copolymer Dispersions for Flexible Packaging
October 17, 2005
Christopher Guy & Norman Seung
Agenda
• Ethylene Acrylic Acid Dispersion History• Overview of Ethylene Acrylic Acid
Chemistry Used• Versatility of Markets and Applications• Limitations of Traditional EAA Dispersions• New and Future Developments with EAA
EAA Dispersion History
• EAA Dispersions have been commercially available since the early 80’s
• Features of Traditional EAA dispersions:– High Acrylic Acid Content (20%)– 100% Waterbased– Surfactant-Free– Runs on Conventional Coating Equipment– FDA and BGVV Approvals
O
OC+
H
HC
H
H
C
H
H
C-
Ethylene Acrylic Acid
H
H
C-
H
H
C-
H
H
C-
H
H
C-
H
C-
H
H
C-
H
H
C-
H
H
C-
H
H
C-
O OHC
H
HC
H
CH
--
Ethylene Acrylic Acid Chemistry
Polyethylene lamellaecontaining no branching
Polyethylene lamellaecontaining branching
Branching and comonomers interfere with the folding process.
Branching in PE decreases the crystallinity.
Effect of Branching on Crystallinity
Typical Properties of Ethylene and Acrylic Acid
Ethylene• Water Resistance• Flexibility• Barrier Properties• Chemical Resistance
Acrylic Acid• Adhesion• Low Heat-Seal
Temperature• Toughness• Optics
Application Requirements
Parameters affecting adhesion• Wettability• Chemical attraction• Flow characteristics of polymer
– Viscosity of aqueous dispersion– Melt-flow of deposited polymer
Surface Wetting
30354045505560
0 20 40 60 80 100
Temperature (deg. C)
Dyn
e / c
m
10% AA20% AA MI 300w/ defoamer20% AA MI 1300Low Visc.w/IPA
Increasing Coating Temperature Lowers Surface Tension
Chemical Attraction
Hydrogen Bonding adds: - melt strength- tensile strength- hot tack
Carboxyl Group
C0
0 HC0
0H
--
+ C0
0 H+
-0C0H
-
+
+
Adhesion to polar substrates
Flow Characteristics
• Shearing stress of the coating can impact the viscosityof EAA dispersions.
Application Specifics
• Applied via low viscosity coating equipment (gravure, flexo, air knife, meyer rod)
• Dry the dispersion to remove water and fuse polymer• Cool coating to 140°F (60°C) to prevent blocking• Aging is not required - can be extrusion coated
immediately • Typical priming coating weights
– Non-porous films and foil - 0.5 to 1.0 g/m²– Paper - 0.8 to 1.2 g/m²
• Typical lamination coating weight– Least porous substrate - 1.6 to 2.4 g/m²
Applicator:gravure
flexomeyer rod
Substrate
Aqueous Dispersion of EAA (10-25% non-volatile)
Drying
(60 – 130°C)
Typical Coating of the Substrate0.5 – 2 g/m2
Application Specifics
Excellent Good Poor(>3lbs/in) (1-3 lbs/in) (<0.5 lbs/in)
Aluminum PE PPSteel EVA PETGlass Nylon PVCPaper CPE EVOHIonomers Copper PCEMAA
180° T-peel test of composite samples
EAA Adhesion Recommendations
Typical Primers Used
• Polyurethane (one and two parts)• Polyester and polyester urethane• Acrylics (various different types)• Polyvinylidene chloride• Polyethylene imine• Vinyl (copolymer and blends)
Agenda
• Ethylene Acrylic Acid Dispersion History• Overview of Ethylene Acrylic Acid
Chemistry Used• Versatility of Markets and Applications• Limitations of Traditional EAA Dispersions• New and Future Developments with EAA
Aqueous inks Metallized Paper Paper saturation
Textile warp sizing Coatings Coated filler
Lamination Flexible packaging Bottle coatings
Paint Fabric coatings Nonwoven binders
Primer / Tie Coat Glass fiber sizing Heat Seal Coatings
Overprint varnishes Can & coil coatings Medical
Possibilities…
Medical
• Medical Device Packaging– Excellent adhesion to Tyvek®– Forms a clear, flexible and breathable film– Enables gas-sterilization– FDA and BGVV Compliant
• Medical Garments– Melt flow reaches 1,300 g/10 min (190°C)– Binder for multiple layer porous sheets
Heat Seal Coatings
• Improving line speeds with– Low heat seal temperature, sealing 20-30°C
lower than polyethylene– Excellent hot tack
• Low viscosity coating allows application on traditional coating equipment
• Pattern Applied if Desired• Thinner films than extrusion coatings• FDA and BGVV compliant
Metallized Paper
• Pre-treatment coating used to prepare base paper to accept metallization
• Improves vaporized aluminum adhesion to paper
• Post-metallizing coating to protect aluminum surface of paper and reduce oxidation
Paper and Film Lamination
• Used as a tie layer• Adhesion to
– Foil, Paper, LDPE, Nylon • Water, grease and oil resistant• Effective at low coating weights• Applied via conventional coating
equipment
Agenda
• Ethylene Acrylic Acid Dispersion History• Overview of Ethylene Acrylic Acid
Chemistry Used• Versatility of Markets and Applications• Limitations of Traditional EAA Dispersions• New and Future Developments with EAA
New Developments
• High Performance Characteristics– Enabling Adhesion to More Substrates – Increasing Bond Strength– Reducing Heat Seal Temperature– Improving Hot Tack– FDA and BGVV Food Compliance
Enabling Adhesion to More Substrates
• Coating adhesion to:– PP – PET– PVC
• New Developments with Michem®Prime show improved adhesion to a wide range of substrates and can eliminate need for a primer.
Bond Strength to LDPE
0
50
100
150
200
250
300
350
400
450
100 110 120 130 140 150 160
Temperature (°C)
Bon
d St
reng
th to
LD
PE (g
MP 48525RMP2960MP498345NMP4983R
Improving Bond Strength
Future Modifications
• Capabilities include modification to:– Water Sensitivity– Heat Seal Temperature– Hot Tack– Foam Control– Rheology Control
Conclusions• Developments in EAA Dispersion
Chemistry have enabled:– Faster line speeds in flexible packaging with
lower heat seal temperatures– Increased Versatility of Substrate Use with
Improved Adhesion to Broad Range of Substrates
– Improved Bond Strength– Broadened Application Ease of Use– Maintained FDA and BGVV Compliance
Contact Information:Christopher Guy9080 Shell RoadCincinnati, Ohio 45236513.793.7766 (p)513.793.2504 (f)[email protected]
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