What Is OPP and CPP Film? Differences and Uses
In packaging, OPP stands for oriented polypropylene film and CPP for cast polypropylene film. Both are made from the same plastic; what separates them is whether the film is stretched during manufacture.
Whether you are buying ready-made OPP or CPP bags or ordering film on the roll, knowing which film a quote refers to makes offers easier to compare. This article covers how the two are made, where BOPP fits in, why they are so often laminated together, and how food-contact suitability is demonstrated in the EU.
What is OPP film?
OPP is polypropylene film that has been stretched during production. After extrusion the film is drawn on a tenter frame and then annealed, which gives it directional properties (source).
Polypropylene film can be produced in three forms: as a cast film, as a biaxially oriented film (BOPP), or as a uniaxially oriented film (source). OPP is the umbrella term used for all oriented polypropylene films.
What is BOPP, and how does it differ from OPP?
BOPP is biaxially oriented polypropylene: film that is stretched both in the machine direction and across it. Biaxial orientation increases the film’s strength and clarity (source).
It is made either on a bi-directional stenter line or by double-bubble blown film extrusion (source). Strictly, BOPP is the biaxially oriented type of OPP; if the distinction matters for your application, the supplier’s technical data sheet is where to confirm it.
What is CPP film?
CPP is polypropylene film produced without orientation. The melt is extruded, cooled and wound directly onto a roll (source).
One film manufacturer describes CPP as soft, like polyethylene, while BOPP is stiffer and crinkly (source). The property that matters most in packaging, though, is that CPP seals with heat, covered in its own section below.
What are the differences between OPP and CPP?
The core difference between OPP and CPP is orientation: OPP is stretched during manufacture, CPP is not. Most of the differences in stiffness, feel and heat-seal behaviour follow from that single step.
| OPP / BOPP | CPP | |
|---|---|---|
| Full name | Oriented (BOPP: biaxially oriented) polypropylene | Cast polypropylene |
| Process | Extrusion, then stretching in one or two directions | Extrusion and cooling, no stretching |
| Feel | Stiffer, crinkly | Soft, close to polyethylene |
| Heat sealing | Poor on its own; a sealing layer is added | Seals without special coatings |
| Role in a laminate | Printed outer film | Heat-sealing inner layer |
Sources: plastic film, BOPP, CPP compared with BOPP, BOPP heat sealability, BOPP/CPP laminate.
Why are OPP and CPP used together?
OPP and CPP are paired so often because of heat sealing. BOPP on its own is unsatisfactory in heat sealability, so a heat-sealing resin is laminated onto one or both of its surfaces, or co-extruded with it (source).
CPP, by contrast, can be sealed thermally or ultrasonically without any specialty coating (source). That is why the two are so often laminated: in a common structure described by another film manufacturer, CPP is laminated with printed BOPP film to form a BOPP/CPP two-layer film (source).
Where are OPP and CPP used?
Both films are common in food packaging. BOPP is widely used to pack snack foods, fresh produce and confectionery, as well as for labels, and is regarded as one of the most important commercial polyolefin films (source).
Typical uses for CPP include bakery and confectionery packaging, food wraps and laminations (source). We cover the printing side of packaging film in our article on flexographic printing.
Is OPP the same as polyethylene (PE) film?
No. OPP and CPP are polypropylene (PP), while the LDPE, MDPE and HDPE common in bags are polyethylene (PE). Both belong to the polyolefin family, but they are different plastics.
Polypropylene has a density of 0.895–0.93 g/cm³, and commercial grades melt at 160–166 °C; it is slightly harder and more heat-resistant than polyethylene. Its resin identification code is also different: polypropylene is marked 5 (source). The polyethylene grades are covered in our article on polyethylene.
Are OPP and CPP suitable for food contact?
Whether a film is suitable for food contact is shown by regulatory compliance and testing, not by the name of the polymer. In the EU, the framework for all food contact materials is Regulation (EC) No 1935/2004, and the most detailed specific measure for plastics is Regulation (EU) No 10/2011 (source).
That regulation sets an overall migration limit of 10 mg per dm² of contact surface for the total of substances passing into food (source). For an EU importer, the practical answer to “is OPP food safe?” is therefore a document for the specific product: a declaration of compliance and the supporting test results.
What applies at DEKA Plastik
DEKA Plastik does not produce OPP or CPP film. As recorded in our PPWR technical file, these films are sourced as ready-made reels from approved suppliers and are then flexographically printed, slit, cut and sealed at our facilities. The film we extrude ourselves is polyethylene (LDPE, MDPE and HDPE).
We apply flexographic printing in up to eight colours. Lamination is not done in-house: for laminated products the film is either bought in already laminated or the film we source is sent out for lamination.
We use OPP and CPP, as ready-made bags or as film on the roll, in the following products:
- Food packaging: dry food packaging, roll bread packaging and bakery product packaging
- Film on the roll: printed, unprinted and automatic filling rolls, plus laminated rolls whose layers are OPP and CPP
- Garment packaging: the OPP/CPP variant of our underwear packaging and outerwear packaging
In our food packaging, production is always food-contact grade and uses virgin polymer only; compliance is declared under Regulation (EU) No 10/2011, Regulation (EC) No 1935/2004 and the Turkish Food Codex. For film on the roll, food-contact grade is supplied on request. Production runs under ISO 9001:2015 and ISO 22000:2018 certified management systems.
One boundary we state plainly for EU buyers: the material composition declaration we prepared under the PPWR covers PE bags only. OPP and CPP products fall outside its scope. Details are on our PPWR compliance page.
To work out whether your product needs OPP, CPP or a laminated structure, get in touch.