Aroma Barrier & Low Extractables


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Learn how TOPAS COC can improve aroma barrier and product purity. TOPAS resin also delivers many other benefits - moisture protection, easy forming, high shrink, easy opening, superb twist, and more.

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Aroma Barrier & Low Extractables

  1. 1. 2005 PLACE Conference September 27-29 Las Vegas, Nevada TOPAS Cyclic Olefin Copolymers in Food Packaging – High Aroma Barrier Combined with Low ExtractablesPresented by:Randy JesterAssociate Engineer
  2. 2. TOPAS® COC A New Addition to the Ethylene Copolymer Family  Polyolefin Resin  Amorphous  Clear and Colorless  High Purity  High Moisture Barrier  Good Chemical Resistance  Easy to Process2
  3. 3. Production Plant in Oberhausen, Germany  Production plant on stream since Oct 2000  30 000 tons / year production capacity  Backward integrated in Norbornene  Largest Cyclic Olefin Copolymer (COC) plant in the world Large scale production of COC enables the production of a cost competitive product for use in packaging applications3
  4. 4. COC - Synthesis and Structure H 2C CH2 +  Readily available raw Ethylene Cyclopentadiene Norbornene materials  Highly efficient catalyst + H 2C CH2  Low usage  Catalyst removed as part of Metallocene process Catalysis  High purity product ( )( m ) n  Amorphous  Crystal clear COC4
  5. 5. COC is Amorphous The COC molecule is a chain of small CH2-CH2 links randomly interspersed with large bridged ring elements It cannot fold up to make a regular structure, i.e., a crystallite NB NB NB NB COC has no crystalline melting point, but only a glass transition temperature, Tg , at which the polymer goes from “glassy” to “rubbery” behavior5
  6. 6. COC - Basic Properties Glass transition temperatures, °C(°F)  Glass Clear, Transparent  Glass clear, Transparent 33 - 180 (91 – 356)  Sterilizable via Steam, EtO, Modulus of elasticity, N/mm2 (kpsi) gamma, beta (E-beam) 1260 – 3200 (180 – 460)  Resistant to Alcohols, Acids, Tensile strength, N/mm2 (kpsi) Bases, Polar Solvents 25 - 63 (3.6 - 9.1)  High Purity, Low Extractables Density, g/cm3 1.02  Low Water Transmission Rate Water uptake, % (WVTR) < 0.01  Biocompatible WVTR, g-mil/100 in2 × day (38°C/90%RH) 0.24 – 0.49  Halogen-free6
  7. 7. COC – Regulatory Status  FDA Regulation 21 CFR 177.1520 (3.9)  COC FDA Food Contact Notification (FCN #75) became effective August 22, 2000, covers films, sheets, and articles made therein from and molded articles for repeated use.  COC FDA Food Contact Notification (FCN #405) became effective May 20, 2004, expands #75 to cover all applications, including bottles.  FDA Drug Master File, DMF# 12132, established.  FDA Device Master File, MAF# 1043, established.  The monomers are listed in the EU Directive 2002/72/EG  Norbornene has a SML = 0.05 mg/kg. COC can meet all major regulatory requirements for food contact and medical use7
  8. 8. 23C/50% TOPAS® COC - Barrier Properties 10 000 Oxygen Barrier [cm3·mil/100 in2·atm·d] 1 000 LDPE EVA12 PCL HDPE PC BOPP Cellulose Acetate 100 PP PS PVC ® COC plasticized TOPAS PVC hard 10 PET PA 6 PCTFE Starch PEN 1 PAN MXD PVdC Cellulose 0.1 EVOH LCP Sources: Permeability Properties of Plastics and Elastomers, Massey, 2nd Edition; various datasheets; internal data 0.01 0.01 0.1 1 10 100 1 000 10 000 Water Vapor Barrier [g·mil/100 in2·atm·d] 38C/90% COC can extend the shelf life of products due to its very high moisture barrier8
  9. 9. COC in LLDPE blends can reduce gas/vapor transmission rates by 70 – 90% at blend levels as low as 80%. This blend level typically achieves >90% of the barrier of 100% COC.9
  10. 10. Reduced Flavor Scalping Scalped d-Limonene 1400.00 1195.08 1200.00 1110.76 Concentration (ng/cm2) Purge & Trap-Thermal 1000.00 Desorpt ion-GC-M S Analysis Dat a 800.00 600.00 400.00 200.00 0.00 100% COC 100% LLDPE Scalping of d-Limonene by COC is similar to that of LLDPE, indicating that the solubility of d-Limonene in COC is similar to that of LLDPE10
  11. 11. Factors Affecting Permeability  Permeability (normalized transmission) is the product of diffusivity (kinetic factor) and solubility (thermodynamic factor).  The similar levels of equilibrium scalping indicate that solubility of d-limonene is similar in LLDPE and COC.  This information indicates that the primary factor affecting the reduced permeability of COC is diffusivity.11
  12. 12. Glassy vs. Rubbery State  The COC grades in this study have Tg’s in the 68-80oC range, well above the measurement conditions. LLDPE on the other hand has a Tg of –128oC and is in a rubbery state.  Polymers in the rubbery state typically have a higher free volume due to a high level of molecular mobility, which increases diffusion rates of permeants.  Polyethylene and COC are both non-polar materials and would in general have similar solubility parameters for most permeants.  It can be generalized that for many permeants, COC will produce an improved barrier as compared to polyethylene since it will typically be in the glassy state under use conditions.12
  13. 13. Reduced Extractables Elevated temperature (60oC for 24 hours) extraction shows that COC has significantly lower extractables than LLDPE including about 50% lower oligomer levels which can produce off tastes in food13
  14. 14. Conclusions  COC has better aroma barrier than polyethylene and can reduce aroma/flavor loss from food when it is utilized as a barrier layer in food packaging.  COC can also reduce the transmission of objectionable odors to surrounding areas and should have utility in disposable food storage bags.  Low extractables in COC reduces the possibility of generating an “off- taste” in water or susceptible foods when used as a contact layer or just under a seal layer in packaging.14