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 EngineerTicona LLC
COC - A New Family of Thermoplastic Materials Olefinic Resin Amorphous, Clear and Colorless High Purity High Moisture Barrier Good Chemical Resistance Easy to Process2
Ticona’s COC 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
COC - Synthesis and Structure H2 C CH2 + Readily available raw Ethylene Cyclopentadiene Norbornene materials Highly efficient catalyst + H2 C CH2 Low usage Metallocene Catalyst removed as part Catalysis of process ( )(m )n High purity product Amorphous Crystal clear COC4
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
COC - Basic Properties Glass transition temperatures in [°C] Glass clear, Transparent 70 - 180 Modulus of elasticity in [N/mm2] High UV Transmission 2600 - 3200 Resistant to Alcohols, Acids, Tensile strength in [N/mm2] Bases, Polar Solvents 66 High Purity, Low Extractables Density in [g/cm3] 1.02 Low Water Transmission Rate (WVTR) Water uptake in [%] < 0.01 Biocompatible Water permeability in [g × mm/m2 × day] 0.02 - 0.04 Halogen-free6
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 meets all major regulatory requirements for food contact and medical use7
COC - Barrier Properties 10000 LDPE EVA/PE PCL PS Oxygen Permeability [cm3/m2*d*bar] 1000 HDPE PVC BOPP PC PP plasticized Cellulose Acetate 100 COC PVC hard PET 10 Starch PEN PA 6 PAN 1 PVDC Cellulose 0,1 EVOH Film thickness: 100 µm LCP 0,01 0,01 0,1 1 10 100 1000 10000 Water Permeability [g/m2*d] COC can extend the shelf life of products due to its very high moisture barrier8
LLDPE 80% COC / 20% LLDPE 1 0.9 Relative Transmission Rate 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Oxygen* Water** d-limonene*** Onion*** Sardine*** * 23C & 50% RH ** 38C & 90% RH *** 23C, MOCON technique, saturated vapor of “paste” COC in LLDPE blends can reduce transmission rates by 70 to 90% for gases/vapors at blend levels as low as 80%. This blend level9 typically achieves >90% of the barrier properties of 100% COC.
Scalped d-Limonene 1400.00 1195.08 1200.00 1110.76 Concentration (ng/cm2) 1000.00 Purge & Trap-Thermal Desorption-GC-M S Analysis Data 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
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
Glassy vs. Rubbery State The COCs 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
10% ETOH Extractables (major components) 40 35 oligomers (etoh extract) Concentration (ng / cm ) 3 30 Total etoh extractables 25 20 15 10 5 0 100% COC (80C Tg) 100% LLDPE 100% COC (68C Tg) 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
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
I would like to thank the following people at Ticona for their contributions to this paper: •Adam Barton •Robert Roschen •Rick Vliet •Arno Wolf15
Thank YouPRESENTED BYRandy JesterEngineer AssociateTicona LLCrandy.firstname.lastname@example.org Please remember to turn in your evaluation sheet...