Cyclic olefin copolymer (COC) is an amorphous polymer made by several polymer manufacturers. COC is a relatively new class of polymers as compared to commodities such as

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins a ...

and

polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...

. This newer material is used in a wide variety of applications including packaging films, lenses, vials, displays, and medical devices.

Various types

In 2005 there were "several types of commercial cyclic olefin copolymers based on different types of cyclic monomers and polymerization methods. Cyclic olefin copolymers are produced by chain copolymerization of cyclic monomers such as 8,9,10-trinorborn-2-ene (

norbornene Norbornene or norbornylene or norcamphene is a highly strained bridged cyclic hydrocarbon. It is a white solid with a pungent sour odor. The molecule consists of a cyclohexene ring with a methylene bridge between carbons 1 and 4. The molecule car ...

) or 1,2,3,4,4a,5,8,8a-octahydro-1,4:5,8-dimethanonaphthalene (tetracyclododecene) with ethene (such as Polyplastics subsidiary TOPAS Advanced Polymers' TOPAS, Mitsui Chemical's APEL), or by

ring-opening metathesis polymerization Ring-opening metathesis polymerization (ROMP) is a type of olefin metathesis chain-growth polymerization. The driving force of the reaction is relief of ring strain in cyclic olefins (e.g. norbornene or cyclopentene). A variety of heterogeneous ...

of various cyclic monomers followed by hydrogenation (Japan Synthetic Rubber's ARTON, Zeon Chemical's Zeonex and Zeonor)." These later materials using a single type of monomer are more properly named cyclic olefin polymers (COP).

Chemical and physical properties

Typical COC material has a higher modulus than HDPE and PP, similar to PET or PC. COC also has a high moisture barrier for a clear polymer along with a low moisture absorption rate. In medical and analytical applications, COC is noted to be a high purity product with low extractables. COC is also a

halogen The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this grou ...

-free and

BPA BPA may refer to: Organizations *BPA Worldwide, an organization that audits circulation figures for mass media *Banca Privada d'Andorra * Bangladesh Police Academy *Blue Panorama Airlines, ICAO code *Bonneville Power Administration, a U.S. powe ...

-free product. Some grades of COC have shown a lack of

estrogenic Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...

activity.{{Cite journal , title=Yang et al (July 2011), "Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem That Can Be Solved" ''Environmental Health Perspectives'' , year=2011 , doi=10.1289/ehp.1003220 , pmid=21367689 , s2cid=18809650 , last1=Yang , first1=C. Z. , last2=Yaniger , first2=S. I. , last3=Jordan , first3=V. C. , last4=Klein , first4=D. J. , last5=Bittner , first5=G. D. , journal=Environmental Health Perspectives , volume=119 , issue=7 , pages=989–996 , pmc=3222987 The optical properties of COC are exceptional, and in many ways very similar to glass. COC materials offer exceptional transparency, low

birefringence Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are said to be birefringent (or birefractive). The birefri ...

, high Abbe number and high heat resistance. The moisture insensitivity of COC is often an advantage over competing materials such as polycarbonate and acrylics. The high flow of COC enables higher aspect ratio (squatter and shallower) optical component fabrication than other optical polymers. High ultraviolet transmission is a hallmark of COC materials, with optimized grades the leading polymer alternatives to quartz glass in analytical and diagnostic applications. Some properties vary due to monomer content. These include

glass transition temperature The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or ru ...

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the int ...

, and

stiffness Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a ...

. The glass transition temperature of these polymers can exceed 200°C.IUPAC Technical Report (2005)
/ref> COC resins are commonly supplied in pellet form and are suited to standard polymer processing techniques such as single and twin screw

extrusion Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...

, injection molding, injection blow molding and stretch blow molding ( ISBM), compression molding, extrusion coating, biaxial orientation,

thermoforming Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or "film" when referring to thinner gauges and cert ...

and many others. COC is noted for high dimensional stability with little change seen after processing. COC and COP are generally attacked by non-polar

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

s, such as

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) ...

. COC shows good chemical resistance and barrier to other solvents, such as

alcohols In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which is ...

, and is very resistant to attack from acids and bases. Electronic properties of COC are in some respects similar to fluoropolymers, most notably a similarly low

dissipation factor In physics, the dissipation factor (DF) is a measure of loss-rate of energy of a mode of oscillation (mechanical, electrical, or electromechanical) in a dissipative system. It is the reciprocal of quality factor, which represents the "quality" or ...

or tan delta, and low permittivity. It is a very good insulator.

Applications

Packaging

COC is commonly extruded with cast or blown film equipment in the manufacture of packaging films. Most often, due to cost, COC is used as a modifier in monolayer or multilayer film to provide properties not delivered by base resins such as

. Grades of COC based on ethylene show a certain amount of compatibility with polyethylene and can be blended with PE via commercial dry blending equipment. These films are then used in consumer applications including food and healthcare packaging. Key COC enhancements can include thermoformability, shrink, deadfold, easy tear, enhanced stiffness, heat resistance and higher moisture barrier. Common applications include shrink films and labels, twist films, protective or bubble packaging, and forming films. Another noted application which often relies on a high percentage of COC in the end product is pharmaceutical blister packaging.

Healthcare

The high purity, moisture barrier, clarity, and sterilization compatibility of COC resins make them an excellent alternative to glass in a wide range of medical products. Breakage prevention and weight reduction are common reasons for choosing COC in these applications. COC has a very low-energy and nonreactive surface, which can extend shelf life and purity of medications such as insulin and other

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

drugs in applications such as vials, syringes and cartridges. The high UV transmission of COC also drives diagnostic applications such as

cuvettes A cuvette ( French: cuvette = "little vessel") is a small tube-like container with straight sides and a circular or square cross section. It is sealed at one end, and made of a clear, transparent material such as plastic, glass, or fused quartz. ...

and microplates. COC plays an increasingly important role in microfluidics due to its chemical resistance, clarity and unusually high mold detail replication which makes it possible to reliably mold submicron features. Most COC grades can undergo sterilization by

gamma radiation A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically s ...

, steam, or ethylene oxide.

Optics

These polymers are commercially used in optical films, lenses, touch screens, light guide panels, reflection films, and other components for mobile devices, displays,

cameras A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...

, copiers and other optical assemblies.

Fiber spinning

COC has unique electrical properties that resist

dielectric In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the ma ...

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.Lamonte, Ronald & Donal McNally (June 2000), "Uses and Processing of Cyclic Olefin Copolymers" ''Plastics Engineering''

Electronics

The low dielectric constant of COC, even at high frequency, has led to its use in certain

antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

applications as well as

capacitors A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a ...

requiring higher temperature resistance than

can provide.

References

External links

Physical and electrical properties of TOPAS
Polymer chemistry Copolymers