BOPP, BOPET and CPP: Which Film Should You Use?

BOPP, BOPET and CPP account for the large majority of flexible packaging film consumption worldwide. They are often discussed as interchangeable, which is the fastest way to an under-performing pack. Each has a distinct profile, and once you understand where the differences actually matter, selection becomes straightforward.

BOPP: the cost and converting workhorse

Biaxially oriented polypropylene offers excellent moisture barrier, good clarity, high stiffness at low gauge and a wide range of surface treatments. It runs well on fast film-fed equipment, which is why it dominates snack, pasta, bakery and overwrap applications. Its limitations are heat stability at elevated sealing temperatures, limited puncture resistance compared with polyester, and a relatively high oxygen transmission rate compared with coated or metallised grades.

BOPET: strength, thermal stability and print quality

Biaxially oriented polyester is roughly six to ten times stronger than a comparable polypropylene film and holds its dimensional stability across a far wider temperature range. That makes it the standard base for thermal transfer ribbon, for label face stock, for the print layer of retort structures and for metallised laminates. Polyester also accepts heat, which is exactly what a laminate or an evaporation coating run requires. Its cost per kilogram is higher, but converters frequently find that a thinner or simpler structure offsets that difference.

CPP: sealing without the coating step

Cast polypropylene is extensible, not oriented, and heat-seals as the cast film is made. That removes an entire coating pass, and with it the solvents, energy and line space that conversion normally costs. CPP is widely used for stand-up pouches, snack wrappers and as the sealing layer in paper-based laminations where recyclability is a priority.

Barrier is never a property of one film

The water-vapour and oxygen transmission figures printed on a film datasheet describe that film alone. The pack you ship has a substrate, an adhesive, possibly a metallised layer and often printed ink. A 25 micron BOPP with an EVOH or alumina coating can outperform a heavier plain film by a wide margin. Always ask for barrier data on the finished structure and, where relevant, under the humidity and temperature profile the pack will actually experience.

Metallisation changes the decision

When a structure is vacuum-deposited, the barrier is supplied by the aluminium layer and the substrate's job is mechanical. That reverses part of the usual reasoning: a BOPET base becomes preferable not for its barrier but for its dimensional stability during the deposition run and its resistance to the heat involved. Conversely, an oriented polypropylene base is lighter and cheaper, but the web must be handled gently.

A simple decision sequence

Ask three questions in order. First, does the pack need hot-fill, retort or a demanding heat-seal window - if yes, look at CPP or BOPET-based structures. Second, does it need an oxygen barrier - if yes, plan for a coating or metallised layer and specify the required transmission rate. Third, is it a short shelf-life, high-volume pack where cost dominates - if yes, BOPP with a heat-seal coating will usually win. Answer those three and the film choice is largely determined.

Asia Pacific Industry Group supplies BOPP, BOPET and CPP in grades matched to all three of these routes, and our technical team can build the comparison table around your specific pack so you can evaluate actual options rather than generic data.