The Effect of Retort Conditions on Clear High Barrier Laminated Structures Celplast Metallized Products Ltd. Presented at the AIMCAL Fall Technical Conference October, 2005
Outline Retort pouch markets Clear barrier retort film technology Clear barrier laminations & retorting trials Barrier test results Conclusions
Retort Pouch Markets Drivers to replace cans & glass jars: Lighter weight Safer - no sharp edges Faster heating leads to more even cooking & better taste
Retort Pouch Markets Typical 4-ply MRE foil retort pouch structure: Polyester Ink Adhesive Nylon Adhesive Aluminum Foil Adhesive Cast Polypropylene
Retort Pouch Markets Drivers to use clear retort pouches: Visibility of product Microwavable Use with metal detectors Use with RFID tags
Retort Pouch Markets Several different products available on market: Silicon oxide coated PET Silicon oxide coated nylon Aluminum oxide coated PET Poly (acrylic acid) coated PET PVdC coated PET EVOH blown film
Retort Pouch Markets Drivers to use oxidecoated clear retort films: No yellowing Environmentally acceptable No retort shock Excellent chemical & odor resistance
Retort Pouch Markets Drivers to use solventless adhesives: Rising solvent costs Rising energy (dryer) costs EPA requirements Lower overall material usage
Retort Pouch Markets Typical 4-ply clear barrier retort pouch structure: Polyester Ink Adhesive Oxide-coated Polyester Adhesive Nylon Adhesive Cast Polypropylene
Retort Pouch Markets Possible 3-ply clear barrier retort pouch structures: Polyester Ink Adhesive Oxide-coated PET Adhesive Cast Polypropylene Polyester Ink Adhesive Oxide-coated Nylon Adhesive Cast Polypropylene
Clear barrier retort film Rewinder technology Unwinder Plasma pretreatment Electron beam evaporation
Clear barrier retort film technology Silicon-oxide coated films: Available on both nylon & PET substrates Improved processability Widely accepted in many packaging applications Excellent flex-crack resistance (Gelbo flex tests) compared to aluminum-oxide coated films
Clear barrier retort film technology Oxygen Permeation After Retorting And Gelbo Flexing for 48 g PET Films in Solvent-based Laminations OTR, cc/m2/day @50%RH, 23 C 2.5 2 1.5 1 0.5 0 post retort post retort 5x post retort 10x post retort 50x SiOx PET(1) SiOx PET(2) AlOx PET (1) AlOx PET (2)
Clear Barrier Laminations and Retorting Trials Structures evaluated: #1 48 g PET / SiOx-coated 48 g PET / 60 g nylon / 3 mil CPP #2 48 g PET / SiOx-coated 48 g PET / 3 mil CPP #3 48 g PET / SiOx-coated 60 g nylon / 3 mil CPP
Clear Barrier Laminations and Retorting Trials Rohm & Haas adhesives evaluated: Solventless aliphatic PUR inner plies Solvent-based aromatic PUR outer plies Henkel adhesives evaluated: Solventless aliphatic PUR #1 inner ply Solventless aliphatic PUR #2 outer plies
Clear Barrier Laminations and Retorting Trials Retort test conditions - Rohm & Haas: Carried out at 121 C for 1 hour Retorted both laminated strips and waterfilled pouches suspended in retort chamber Retort test conditions - Henkel: Carried out at 121 C for 1 hour Retorted pouches only One set filled with water, one set with vegetable oil
Barrier Test Results Oxygen barrier testing: Carried out at 23 C, 50%RH Samples tested on MOCON 2/21 and Lyssy OPT oxygen transmission rate test units Water vapor barrier testing: Carried out at 37.8 C, 90%RH Samples tested on MOCON Permatran W and Lyssy L80-5000 water vapor transmission rate test units
OTR Test Results R&H
WVTR Test Results R&H
OTR Test Results - Henkel
WVTR Test Results - Henkel
Conclusions Silicon oxide coated PET performed well in both 3-ply and 4-ply structures Silicon oxide coated nylon barrier was compromised by 2-5x after retorting Vegetable oil in pouches was more aggressive in compromising barrier properties than water in pouches
Conclusions 3-ply pouches of PET/SiOx-PET/CPP structure exhibited more stress whitening after retorting than nyloncontaining structures Aliphatic solventless adhesive used between all plies gave better post-retort WVTR properties than structures with aromatic solventless adhesive; OTR was similar in both structures
Acknowledgments Tom Mueller of Rohm & Haas Grant Kenion of Henkel Adhesives Scott Whiteside of Clemson University
THANK YOU! Any questions?
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