BOPP film is biaxially oriented polypropylene, a plastic film made from polypropylene that has been stretched in two directions to dramatically improve its strength, clarity, and barrier properties. It’s one of the most widely used packaging materials in the world, wrapping everything from potato chip bags to candy bars to shipping labels. If you’ve ever noticed how a snack bag feels thin yet surprisingly tough and crystal clear, you were probably holding BOPP.
How BOPP Film Is Made
The “biaxially oriented” part of the name describes the manufacturing process that gives this film its distinctive properties. Polypropylene resin is first melted and extruded into a thick sheet. That sheet is then stretched in the machine direction (the direction it travels down the production line) and again in the transverse direction (side to side). This two-way stretching aligns the polymer chains in both directions, which is what transforms ordinary polypropylene into a much stronger, clearer, and more useful material.
The stretching process is what separates BOPP from regular polypropylene film. Unstretched polypropylene is relatively soft and hazy. After biaxial orientation, the film becomes thinner, stiffer, and highly transparent, with tensile strength around 113 MPa in the machine direction and 102 MPa in the transverse direction. For context, that’s strong enough to resist tearing during high-speed packaging while remaining thin enough to feel almost weightless.
Thickness and Specifications
BOPP films typically range from 15 to 50 micrometers (µm) thick. To put that in perspective, a human hair is about 70 µm, so even the thickest BOPP films are thinner than a strand of hair. Thinner films in the 15 to 30 µm range are used for flexible packaging like food wrappers and bag liners. Thicker films from 30 to 50 µm go into applications that need more durability, such as laminating documents or creating rigid label stock.
Why It’s the Go-To Packaging Film
BOPP dominates food packaging because it checks nearly every box the industry cares about. It blocks moisture well, resists oxygen transmission, seals easily with heat, prints beautifully, and costs less than most alternatives. Its water vapor transmission rate stays low under normal storage conditions, though it does climb as humidity and temperature increase. Oxygen permeability, interestingly, decreases slightly at higher humidity levels.
The film’s clarity and gloss make products look appealing on shelves, which matters in a market where consumers make split-second purchasing decisions. It also runs smoothly on high-speed packaging machines thanks to its low-friction surface, meaning manufacturers can wrap thousands of units per hour without constant jams or misfeeds.
Polypropylene is approved by the FDA for direct food contact under 21 CFR 177.1520, which covers olefin polymers used as components of food-contact surfaces. This regulatory clearance is one reason BOPP is so prevalent in food applications specifically.
Common Uses by Industry
- Snack foods: Chips, pretzels, popcorn, and similar products rely on BOPP’s moisture barrier to stay crispy. The film’s printability also allows for vibrant, full-color branding.
- Confectionery: Candy and chocolate wrappers need protection from humidity and heat. BOPP handles both while providing a glossy, attractive finish.
- Bakery products: Bread bags, cookie packaging, and pastry wraps use BOPP to maintain texture and flavor while letting customers see the product inside.
- Frozen foods: BOPP holds up at low temperatures without becoming brittle, preventing freezer burn on frozen meals, vegetables, and desserts.
- Labels and tapes: Pressure-sensitive labels on bottles, adhesive tapes, and laminating films all use BOPP as a base material.
Types and Surface Finishes
Not all BOPP looks the same. Manufacturers produce several finish types to suit different product positioning and functional needs.
Clear (glossy) BOPP is the most common variety. It offers high transparency and a shiny finish that lets consumers see the product inside, which builds trust and drives purchases. It runs well on high-speed lines due to its smooth, low-friction surface.
Matte BOPP has a non-reflective, satin finish that feels soft to the touch. It resists fingerprints and scratches better than glossy film, making it popular with luxury and premium brands that want their packaging to convey quality.
Pearlized BOPP has an opaque, pearl-white appearance. It blocks light, moisture, and odors, making it useful for products that are sensitive to those factors. The built-in antistatic properties also reduce dust attraction during processing.
Metallized BOPP is coated with a thin layer of aluminum, giving it a reflective, metallic sheen. This dramatically boosts its barrier properties against light, moisture, and oxygen, extending shelf life for sensitive products like coffee and certain snacks. It’s also used when brands want a premium, foil-like look without the cost of actual foil.
Printing on BOPP Film
One of BOPP’s biggest advantages is how well it accepts printed graphics, but this requires surface preparation. Untreated polypropylene has low surface energy, meaning inks and adhesives won’t stick to it properly. Manufacturers use corona treatment, an electrical process that raises the film’s surface energy to around 38 to 45 dynes per centimeter or higher. At these levels, inks bond reliably and graphics come out sharp and vibrant. Higher dyne levels (50 to 60+) are needed for more demanding applications like metallic inks or specialty coatings.
Recycling and Environmental Considerations
BOPP is polypropylene, which falls under resin identification code 5 (the number inside the triangle on plastic products). It’s worth noting that this code identifies the resin type but does not mean the item is recyclable in your area. Curbside recycling programs vary widely, and thin flexible films like BOPP are often not accepted in single-stream recycling because they can jam sorting equipment.
Some communities have drop-off programs for flexible plastic films, and BOPP can technically be reprocessed into new polypropylene products. In practice, though, the recycling rate for flexible films remains low compared to rigid plastics like bottles and containers. The lightweight nature of BOPP does reduce its environmental footprint in one respect: it uses less raw material per package and generates lower transportation emissions than heavier packaging alternatives like glass or rigid plastic.