Flexible Packaging Materials
Flexible packaging materials are the polymers and functional layers that a packaging line forms into film. The structural body comes from a base polymer. A barrier layer and a sealing layer are added when the product requires them. The result is a monomaterial or a multilayer structure.
The most widely used materials are the polyolefins, polyethylene and polypropylene, joined by polyester and by barrier layers such as EVOH. Food contact is governed by Regulation (EC) 1935/2004 and Regulation (EU) 10/2011. Below, the materials are grouped by the role they play in the structure.
This page covers the materials used in flexible packaging, not construction films or office lamination film. Recyclability is not established by a class issued by the film producer. It is assessed on the complete pack and confirmed on the technical data sheet of the structure.
Base polymers, barrier layers and packaging structures
Flexible packaging materials fall into three groups with distinct roles in the film. Each group covers a separate function, and the finished structure combines them according to what the product demands.
Base polymers
Polyethylene, polypropylene and polyester
Polyethylene (PE), polypropylene (PP), polyester (PET) and polyamide (PA) form the structural body of the film. They set mechanical strength, flexibility, sealing behaviour and which recycling stream the pack is designed for.
Barrier layers
EVOH, metallised film and transparent coatings
EVOH, the transparent AlOx and SiOx coatings and a thin metallic layer add barrier to oxygen, to water vapour and to light. They do not form the structural body, they combine with the base polymers.
Packaging structures
Monomaterial and multilayer construction
Monomaterial, with a single base polymer, or multilayer, with two or three polymers combined by coextrusion or by lamination. The finished structure sets the barrier profile and the recycling route.
The role of each group is clearest in the position it occupies inside the finished structure.
The role of each layer in a flexible packaging structure
In a multilayer structure, every layer holds a position and covers a function. The combination of layers gives the total performance of the pack.
| Position in the structure | Function | Typical materials | Key property |
| Outer layer | Mechanical strength and print surface | BOPP, PET, PA | Stiffness, printable surface |
| Barrier layer | Protection against oxygen, water vapour and light | EVOH, AlOx, SiOx, thin metallic layer | High barrier, light blocking |
| Tie layer | Compatibilising chemically incompatible layers | PE-g-MAH, PP-g-MAH | Adhesion between layers |
| Sealant layer | Heat sealing on the packaging line | PE (LDPE, LLDPE), CPP | Low temperature sealing, seal strength |
Monomaterial PE/PE or PP/PP structures combine the support and the sealant in the same polymer and remove the tie layers. Barrier comes from the choice of polymer, or from a thin EVOH layer. That layer stays at the low proportion accepted by the RecyClass criteria.
Monomaterial route and multimaterial laminate route
Every flexible packaging structure answers one question first. Does the pack stay in one polymer family, or combine families to reach performance that one polymer cannot deliver? Barrier, sealing, machine behaviour and recyclability all follow from that answer.
The monomaterial route in polyethylene and polypropylene
Every layer belongs to one polymer family, so the finished pack is designed for a single recycling stream. Monomaterial PP is the stiffer, clearer, glossier route, at home with dry goods and hot filling. Monomaterial PE is the tougher route, with a more forgiving seal, at home in the freezer and on fast, heavy-fill lines. Between them, the two families cover most of what dry and frozen packaging asks for.
The multimaterial laminate route with PET and polyethylene
Different polymer families are bonded into one structure, typically a polyester print web over a polyethylene sealant. That reaches oxygen barrier, stiffness and shelf life that a single family cannot. The cost is the recycling route: the combined structure is not designed for a single stream. PET/PE laminates, the reference barrier duplex, are covered in depth. The wider logic of construction, duplex, triplex, coextrusion and solventless lamination, is on the multilayer laminated structures page.
VLM Poliplast works on both routes, laminating solventless from films specified per project. The choice can therefore follow the requirements of the product, not the range a converter happens to offer. Where those requirements come from, the products and filling lines of each sector, is covered in the industry pages.
Choosing a flexible packaging material for your product and line
The choice starts from four reference points: the packed product, the target shelf life, the recyclability requirement and the packaging line. Each one narrows the list of materials.
Choosing by the packed product
Dry products, snacks and bakery mainly ask for a barrier to water vapour, with low sensitivity to oxygen. A monomaterial PE or PP structure usually covers those requirements. Oxidation sensitive products, such as coffee, nuts or supplements, ask for an oxygen barrier. It is delivered by EVOH or by a thin metallic layer.
Choosing by target shelf life
For a short shelf life, monomaterial PE or PP is usually enough. For a long shelf life the higher barrier comes from multilayer structures. Those use EVOH or a thin metallic layer, for products sensitive to oxygen or to light.
Choosing by recyclability requirement under the PPWR
Monomaterial PE/PE and PP/PP structures are designed for the polyethylene and the polypropylene recycling streams. That holds when they carry a thin EVOH layer at the proportion accepted by the RecyClass criteria. Structures that combine incompatible polymers, or that include a thicker metallic layer, are harder to recycle mechanically. Recyclability is not declared through a class certified by the producer, it is assessed on the complete pack. Regulation (EU) 2025/40, the PPWR, has applied since 12 August 2026. From 1 January 2030 the recyclability grades it sets become a condition for the market. Packaging that does not reach them cannot be placed on it. See how recyclability is assessed by grade. An indicative assessment of a structure can be made with the free tool.recyclass.eu.
Choosing by packaging line: HFFS, VFFS and preformed pouches
On HFFS and flow wrap lines, the sealant layer is usually CPP or PE, with a controlled coefficient of friction. On VFFS lines, with high speeds and lower thicknesses, typical structures are PP/CPP or PE/PE. Preformed pouches accept thicker structures and a higher barrier, typically duplex or triplex laminates.
Each material and each structure below has a dedicated page, with properties, processes and applications.
Monomaterial PE and PP, designed for recycling
Monomaterial PE and PP structures are designed for the polyethylene and the polypropylene recycling streams. That design follows the recyclability requirements of the PPWR. Recyclability is assessed on the complete pack, by grade.
Types of flexible packaging materials
Base polymers: polyethylene, polypropylene, PET and recycled PET
Base polymer
Polyethylene grades for flexible packaging
LDPE, LLDPE and metallocene grades: what density, comonomer, melt flow index, additives and surface energy each control, and how recycled PE differs from virgin.
Base polymer
Polypropylene grades for flexible packaging
Tacticity, the glass transition that governs cold behaviour, homopolymer and copolymer families, oxidation on the tertiary carbon, and where clarity comes from.
Base polymer
PET and BOPET film for flexible packaging
A polyester, not a polyolefin: a glass transition above ambient, what biaxial orientation and heat setting lock in, thermal shrinkage, and why standard BOPET needs a sealant.
Recycled polymer
rPET and food grade recycled PET
Where food grade rPET comes from, what intrinsic viscosity decides, why PET has to be dried, and why food contact is an authorisation held by the recycling process.
Oriented polymer
BOPE film and biaxially oriented polyethylene
What stretching in two directions does to the polymer, how BOPE differs from MDO-PE, and why it is the film that makes an all PE pack possible.
Cast polymer
CPP film and cast polypropylene
Why the chill roll temperature, not the resin, decides whether the film freezes as mesophase or alpha crystal, and what that does to haze and sealing.
Barrier materials: EVOH, metallised film and polyamide
Barrier polymer
EVOH oxygen barrier for flexible packaging
The oxygen barrier layer: what creates the barrier, how ethylene content scales it against moisture tolerance, why humidity reverses it and what a tie layer does.
Barrier layer
Metallised film and the thin metallic layer
A coating a few tens of nanometres thick: why pinholes and not the metal decide the barrier, why optical density is the specification, and how it behaves under flexing.
Barrier polymer
Polyamide film, also known as nylon film
A reference page on the material: BOPA and cast polyamide, puncture resistance, why the oxygen barrier falls with humidity, and how polyamide sits against the recycling streams.
Structures: monomaterial PE and PP, EcoMonoFilm, PET/PE laminates and multilayer construction
Monomaterial
Monomaterial PP for flexible packaging
The all PP route, designed for the polypropylene recycling stream: BOPP and CPP variants, barrier and sealing behaviour, food contact and where the structure fits.
Monomaterial
Monomaterial PE for flexible packaging
The all PE route, designed for the polyethylene recycling stream: LDPE, LLDPE and HDPE variants, the MDO-PE print web, deep freeze duty and forgiving sealing.
Registered range
EcoMonoFilm®, monomaterial PE and PP film
The VLM Poliplast monomaterial range, designed for recycling, with a barrier close to that of multilayer structures. Registered trade mark of VLM Poliplast.
Multimaterial
PET/PE laminates for flexible packaging
The reference barrier duplex: what PET brings, sealing on fast lines, and the honest recyclability trade-off of combining polymer families.
Construction
Multilayer laminated structures
How structures are built: duplex and triplex construction, coextrusion against lamination, solventless bonding and which laminates keep a single recycling route.
Technique
Modified atmosphere packaging and the film it needs
Active and passive MAP, what each gas is for, why carbon dioxide leaves the headspace, equilibrium MAP for respiring produce, and the barrier and seal the film must deliver.
Polypropylene against polyethylene, and where to source the film
When the choice sits between two polymer families, the comparison shows, on each criterion that matters, when one is selected and when the other is. Start with polypropylene against polyethylene, which sets out the melting point, the temperature at which each film embrittles, the sealing window and the separate recycling streams. Once the structure is decided, the sourcing comparisons cover Romania against Turkey, Serbia and Poland as supply destinations for buyers in the European Union.
Related resources on regulation, films and documentation
Sustainability and the PPWR
Recyclability grades, recycled content and the requirements of Regulation (EU) 2025/40.
Packaging film families
The commercial films for HFFS, VFFS and flow wrap lines: specifications and how to order.
Industries and applications
Coffee, supplements, pet food, bakery and fishing bait: what each sector asks of the film.
PPWR glossary
The regulatory terms of flexible packaging, defined and referenced to the source.
Technical glossary
The technical vocabulary of films, structures and converting, explained for buyers.
Technical consultation
A material and structure recommendation for your product and your packaging line.