Cyclic Olefin Co-polymers (COC) are a relatively new class of polymers that have seen significant growth and penetration into the medical device and diagnostics markets. Chemically COC are generally comprised of a rigid ring structure and optionally varying amounts of ethylene and are polymerized using a metallocene catalyst. The most common ring structures are based on norbornene with various substituent groups to tailor properties. There are also commercial resins based on more complex ring structures that lead to higher Tg values.
Figure 1. Representative Structure of COC
Ticona was the highest volume COC producer but sold the business to Daicel Chemical Industries and Polyplastics Co., Ltd who markets under the original trade name TOPAS™. Injection molding and extrusion grade are also marketed as Zeonor™ by Zeon Chemicals, and Apel™ by Mitsui Chemical.
Distinguishing characteristics of COC resins are based on their amorphous character, moderate to high Tg, very high optical clarity, low birefringence and excellent moisture barrier properties. The barrier properties of COC are quite remarkable as shown in the figure below: (more…)
