Polymer/organoclay composites: Opportunities in PE blown films for laminated multi-layer packaging

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Polymer/organoclay compositesOpportunities in
PE blown films for laminated multi-layer
packaging

• Amos Ophir, Shmuel Kenig, Ana Dotan and Daniella
  Millis
• Israel Plastics Rubber Center
• Shenkr College of Engineering and Design
• Ramat-Gan, Israel
• Ronopolidan, Israel
• February 2007

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Outline

• Introduction
• ? Properties of PE films for laminates
• ? Organoclay nanocomposite film for laminates
• Case study PE film for personal care laminates
• ? Organoclay master-batch preparation
• ? Industrial scale blown film production of
  PE/organoclay nanocomposite films
• ? Thermal and mechanical properties
• ? Barrier properties
• ? Sealing and hot tack properties
• Concluding Remarks

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Properties of PE films for laminates

• Balanced stiffness/flexibility
• Puncture resistance
• Barrier to gas, oxygen, water, etc.
• Chemical resistance and stability
• Thermal stability
• Optical appearance (high gloss)
• Bonding capability to BOPET or BOPP
• Sealing properties (peelable, non-peel)

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Organoclay nanocomposite film for laminates

• Polyolefin base materials
• for laminates (as inner liner layer)
• LLDPE/LDPE ( ethylene copolymer, metallocene ?)
• HDPE/MDPE ( ethylene copolymer, metallocene ?)
• HPP/RacoPP ( propylene copolymer, metallocene ?)
• New alternative
• PE(LD,LL)/O-MMT ( ethylene copolymer)

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Organoclay nanocomposite film key issues for
packaging

• Exfoliation
• Compatibility
• Orientation
• Inhibition of re-aggregation
• Inhibition of clay translocation

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Comparison of various PO films for laminated
multi-layer packaging
Process in blown film Heat sealing properties Optical props. Thermal stability Chemical resistance stability Barrier properties Puncture resistance Stiffness/ Flexibility balance
LLDPE/ LDPE
HDPE/ MDPE
HPP/ RacoPP
PE(LD,LL)/o-mmt
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Case study PE film for personal care laminate

• 1. Preparation of organoclay master-batch(20)
• Pre-compound of ternary blend of LLDPE LDPE
  LLDPE-g-MAH
• Mixing compound with 20wt of o-mmt clay (
  Cloisite 15A -Southern Clay), in one step
  compound process in a cascade twin screw
  extrusion system.
• Melt processing temp. 180 - 185ºC
• Screws rpm 350
• Production output rate 200 Kg/h

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Cascade twin screw compounding
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Case study PE film for personal care laminate

• 2. Industrial scale production of PE/organoclay
  nanocomposite blown film (mono layer)
• Films production from a physical blends of the
  following components

organoclay MB(20) EVA (9 VA) LLDPE (C8) LDPE Film type
----- ----- 35 65 LDPE/LLDPE
20 ----- 28 52 LDPE/LLDPE/o-mmt(4)
20 10 28 42 LDPE/LLDPE/EVA/o-mmt(4)
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Blown film production line
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Blown film production data

• Extrusion temperature profile 165 185ºC
• Screw rpm 112
• Production output rate 74 Kg/h
• Line speed 15 m/min
• Head pressure 295 bar
• Blow-up ratio (BUR) 2.88
• Draw down ratio (DDR) 6.16
• Film thickness
• LDPE/LLDPE 60 micron
• LDPE/LLDPE/o-mmt(4) 54 micron
• LDPE/LLDPE/EVA/o-mmt(4) 54 micron

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Case study PE film for personal care laminate

• 3. Film characterization
• (comparison with HDPE/MDPE film)
• Microstructure
• Tensile properties
• Tear propagation properties
• Oxygen permeability properties
• Heat sealing properties

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Microstructure (TEM)

• LDPE/LLDPE/EVA/o-mmt(4) film

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Tensile and tear properties

• Tensile test at 50 mm/min
• Tear propagation test at 250 mm/min

Tear propagation resistance N Youngs modulus MPa Work to break J Elongation at max. load Stress at max. load MPa Elongation at yield Yield stress MPa Film type
----- 7.73 250 291 2.3 3.4 215 565 23.8 16.6 8.7 8.6 8.4 (MD) 10.1 (TD) LDPE/LLDPE
---- 7.32 305 429 8.1 9.9 565 845 28.3 25.9 8.7 8.1 10.7 (MD) 12.9 (TD) LDPE/LLDPE/o-mmt(4)
---- 8.01 293 366 9.8 11.2 598 974 23.3 22.6 9.9 9.5 9.8 (MD) 10.3 (TD) LDPE/LLDPE/EVA/ o-mmt(4)
----- 6.17 426 494 3.9 4.6 299 362 49.8 43.3 6.9 6.5 22.6 (MD) 23.5 (TD) HDPE/MDPE
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Thermal-mechanical properties
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Barrier properties (O2TR)
O2TR cc/m2/day/atm Film type
4100 LDPE/LLDPE 60 micron
1500 LDPE/LLDPE/o-mmt(4) 54 micron
1700 LDPE/LLDPE/EVA/ o-mmt(4) 54 micron
2340 HDPE/MDPE 65 micron
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Heat sealing properties

• Heat-sealing mechanism and role of organoclays
• 1. Organoclays may affect the
• sealing characteristics from
• no seal or non-peel welding to
• controllable peel welding.
• 2. Organoclays may dramatically
• increase the barrier to
• diffusion of gases and vapors
• throughout the sealing region pass.

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Heat sealing properties (cont.)

• Heat sealing characteristics and peeling/tearing
  modes

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Heat sealing properties (cont.)

• Heat sealing characteristics and peeling/tearing
  modes (cont.)

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Heat sealing properties (cont.)

• Heat sealing conditions (two platens set)
• - seal bar width 25.4 mm
• - platen seal pressure 3 bars
• - platen seal dwell time 0.5 sec.
• - platen seal temperature varied from 40
  to 180C
• Peel testing conditions
• - tensile jaws speed 25 mm/min

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Seal strength vs. sealing temperature
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Concluding remarks

• Incorporation of 4wt organoclays in blown film
  LDPE/LLDPE for laminate liners contributes the
  following benefits
• 1. Increases mechanical strength and stiffness
  while conserving the film toughness and tear
  resistance.
• 2. Exerts balanced exfoliation and orientation
  layer of silicate microstructure.
• 3. Dramatically increases the MD and TD
  elongation and balances both directions
  mechanical strength and strain properties.
• 4. Increases thermal-mechanical resistance over
  wide temperature range.
• 5. Advantage over HDPE/MDPE in most mechanical
  tensile and tear properties.
• 6. Increases barrier to O2 transmission by a
  factor of 3, to a level better than HDPE/MDPE.
• 7. Alters the heat sealing properties
  characteristics, while with an addition of
  ethylene copolymer exerts convenient and durable
  peel properties, over the tradition non-peel
  behavior of the rests.

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Acknowledgements

• Shenkar/IPRC
• Shmuel Kenig
• Ana Dotan
• Irena Belinsky
• Shura Muchelov
• PennState (US)
• Matt Heideker
• Ronopolydan
• Daniella Millis