Cyclic Olefin Copolymer

Cyclic Olefin Copolymer (COC) is an amorphous polymer made by several polymer manufacturers. COC is a relatively new class of polymers when compared to polypropylene and polyethylene. This material is primarily used in applications requiring glass-like clarity including lenses, vials, monitors, and medical devices.

Chemical and physical properties
COC has a transparency similar to glass in its natural form. Typical COC material will have a higher modulus than HDPE and PP. Due to its chemistry, the higher the modulus, the more brittle it becomes. COC also has a high moisture barrier for a clear polymer along with a low absorption rate. In medical applications, COC is noted to be a high purity product with low extractables. COC is also a halogen-free product.

Some properties will vary due to monomer content. These include glass transition temperature, viscosity, and stiffness. The glass transition temperature of these polymers can exceed 150 °C.

Extrusion
COC can be extruded with both cast and blown film equipment. These films are then used in consumer applications including food and pharmaceutical packaging. Commercial structures of COC used in blister packs are typically coextruded with a thick COC core and thin polypropylene skin layers. PVC and PvDC can also be placed on the skins via lamination. Profile extrusion is another method that can be used to make COC reinforced tubes or pipes.

Molding
While there are many different types of molding, COC is primarily used in injection molding. Its natural clarity makes it useful in lenses for cameras, projectors and copiers. COC has little to no extractables which make it useful in diagnostic and medical devices. Most COC grades can also undergo sterilization by gamma radiation, steam and ethylene oxide.

Fiber Spinning
COC has unique electrical properties that resist dielectric breakdown and have a very low dielectric loss over time. Because of this COC is used in filter media that require a charge retention to work properly.