HomePET Knowledge BaseBOPP vs. BOPET: The Battle of Flexible Films

BOPP vs. BOPET: The Battle of Flexible Films


Welcome to the fascinating world of flexible packaging films! Today, let's delve into a comparison that often stirs curiosity among both industry insiders and everyday consumers alike: BOPP versus BOPET. What makes these films distinct, and why should you care? Well, whether you're a snack enthusiast wondering about the magic behind your crisp packaging, or a tech-savvy individual interested in material science, this exploration is for you!


What Are BOPP and BOPET?


Before we dive into the depths of comparison, let’s clarify what we’re discussing. BOPP stands for Biaxially Oriented Polypropylene, and BOPET is Biaxially Oriented Polyester, with the 'E' typically standing for ethylene. These terms might sound like something out of a complex science textbook, but they're actually quite straightforward once broken down.


The Making of the Films


Both BOPP and BOPET undergo a process known as biaxial orientation. This involves stretching the film in two directions (machine direction and cross direction) during production. This process enhances their mechanical properties, making the films thinner, stronger, and more resistant to various stresses than films produced by simpler methods like blowing or casting.


The Process Explained:


1. Extrusion: It starts with melting down the polymer and forming it into a sheet.

2. Quenching: The sheet is rapidly cooled down.

3. Stretching: The film is then stretched in both the machine direction (MD) and cross-machine direction (CD).

4. Setting: Finally, the properties of the film are set through a heat treatment process.


Key Differences in Properties




  • Moisture Barrier: BOPP is particularly known for its excellent moisture barrier properties, making it an ideal choice for packaging products that need to stay dry, like crisps and other snacks.


  • Lightweight: It has a lower density, meaning you get more film per pound, a cost-effective feature for mass production.


  • Applications: Beyond snack packaging, BOPP is used in labels, tapes, and other products where moisture resistance is crucial.




  • Heat Resistance: BOPET excels in environments requiring high heat resistance. It can withstand temperatures that BOPP cannot, making it suitable for microwaveable meal packaging and other heat-intensive applications.


  • Strength and Rigidity: BOPET is stiffer, offering better protection for products that need more structural integrity.


  • Barrier Properties: While BOPP excels in moisture resistance, BOPET provides a good balance between oxygen and moisture vapor barriers, making it versatile for various packaging needs.


Applications in Real Life


Imagine you are in a supermarket. The shiny, reflective packaging of chips? That's BOPP at work, protecting the contents from moisture. The sturdy, clear packaging used for pre-cooked meals that you can pop into the microwave? That’s BOPET, ensuring the food can handle the heat without the packaging warping or melting.


Innovative Developments


Technological advancements have also brought us simultaneous biaxial orientation processes, enhancing the mechanical performance and allowing for higher levels of film orientation. This innovation is particularly promising for producing multilayer films that incorporate materials like ethylene vinyl alcohol for improved barrier properties.


Environmental Considerations


In today's eco-conscious world, the environmental impact of packaging materials is more important than ever. Both BOPP and BOPET are recyclable, which helps in reducing the environmental footprint. However, the recycling rates and facilities available can vary significantly depending on the region.


Choosing Between BOPP and BOPET


So, which one should you use? The answer largely depends on your specific needs:


- Choose BOPP for excellent moisture barrier properties and lighter weight applications.

- Opt for BOPET for superior heat resistance, stiffness, and a balanced barrier against gases and moisture.


A Dynamic Duo


In the end, BOPP and BOPET are not so much in a battle against each other but are more like partners in the diverse world of packaging solutions. Each has its strengths and ideal applications, making them invaluable in our daily lives from the supermarket to the kitchen.


So next time you tear open a package, take a moment to appreciate the science behind what keeps your food fresh and your products safe. BOPP and BOPET, though just tiny parts of our massive world, play roles far bigger than themselves. Who knew packaging could be so exciting?


And remember, whether it's BOPP's crispness or BOPET's toughness, both films ensure that what's inside counts but also that what's outside protects and preserves. Happy packaging!

Previous article
Next article