A coated film solves one specific problem: the base film has the mechanical strength the application needs, but not the barrier. Rather than switching substrate or adding a lamination layer, a thin functional coating is applied to the surface of BOPP, BOPET or BOPA — and the film gains the moisture, oxygen or aroma barrier the pack requires, at a fraction of the weight of an extra ply.
Where the pack has to be recyclable in a PE stream, coating is not the only route to removing a ply: a vacuum metallized PE web reaches barrier inside a single polymer family instead.
OLUNRO supplies coated films in eleven standard configurations, and coats, metallizes, laminates and slits in-house. That last point matters more than it sounds. Coating is a surface process, and surface processes fail at the edges — literally. Coating weight, anchorage and coverage have to hold across the full web width and from the first metre of a roll to the last. Because the base film, the coating line and the slitter sit on one site, the coated roll is confirmed before it ships rather than after it fails on your converting line.
PVDC coating: the oxygen and aroma barrier
Polyvinylidene chloride is the workhorse of high-barrier coated films. Applied as a thin aqueous dispersion and dried, it forms a dense, semi-crystalline layer that blocks oxygen, moisture, flavour and aroma simultaneously — a combination that a single-layer film cannot deliver at the same thickness.
Typical reasons buyers specify PVDC:
- Oxygen-sensitive contents — coffee, nuts, processed meat, dairy, prepared foods where oxidative rancidity sets the shelf-life limit.
- Aroma retention and flavour scalping — confectionery and bakery applications where the pack must not absorb its own contents’ volatile compounds.
- Retort and pasteurisation — where the barrier has to survive thermal processing.
- Metal-detector-friendly structures — a coated film provides barrier without the metallised layer that can interfere with detection.
Acrylic coating: barrier plus heat-seal
Acrylic coatings are the pragmatic alternative where PVDC is not required or not preferred. They deliver strong flavour and aroma barrier plus a good heat-seal strength, and they print and laminate cleanly. For many overwrap and label applications, an acrylic coating is the entire specification — no second ply needed.
Where both properties are wanted, a film can carry PVDC on one side and acrylic on the other. That two-sided approach is available in our range and is one of the most requested configurations for form-fill-seal work.
PVDC or acrylic: how to choose
Both are barrier layers. They are not interchangeable, and the choice usually comes down to four questions.
| PVDC | Acrylic | |
|---|---|---|
| Oxygen barrier | High — the reason most buyers specify it | Low to moderate |
| Aroma and flavour barrier | High | High |
| Heat seal | Needs a separate sealant ply | Can be specified as the seal layer itself |
| Retort and pasteurisation | Survives it | Not intended for it |
| Chlorine content | Yes | No |
| Recyclability position | Under pressure in EU design-for-recycling guidance | The easier conversation |
Oxygen-sensitive contents — coffee, nuts, processed meat, dairy. The decision is usually made for you. Acrylic will not hold the shelf life; PVDC will.
Aroma is the problem, not oxygen — confectionery, bakery, tea. Acrylic does the job, and does it without the chlorine question. It can also carry the heat seal, which removes a ply.
The pack is retorted. PVDC is in the conversation. Acrylic generally is not.
Your customer has a recyclability commitment. This changes the answer more often than the barrier data does. See below.
The chlorine question
PVDC contains chlorine, and that one fact now drives a lot of European specification decisions — sometimes past the point the barrier data would have led.
We supply both, so we have no interest in steering you one way. What we will say plainly:
- PVDC’s barrier performance is real. For oxygen-sensitive contents at long shelf life there is currently no drop-in acrylic equivalent.
- Where a brand has committed to a recycling route that excludes chlorinated materials, the honest answer is usually to move the shelf-life target or the format — not to pretend acrylic closes a gap it does not close.
- If a customer is asking you “can we drop PVDC?”, send us the contents and the shelf-life target. We will tell you whether acrylic gets there. If it does not, we will say so.
That last point is worth more than a datasheet claim. A supplier who tells you acrylic is equivalent when it is not costs you a failed shelf-life test three months later — and by then the print run is already booked.
The eleven configurations we supply
| # | Base film | Coating configuration |
|---|---|---|
| 1 | BOPA (Nylon) | PVDC, one side |
| 2 | BOPET (Polyester) | PVDC, one side |
| 3 | BOPET (Polyester) | PVDC, two sides |
| 4 | BOPET (Polyester) | Acrylic, one side |
| 5 | BOPET (Polyester) | PVDC one side + Acrylic one side |
| 6 | BOPP | Acrylic, one side |
| 7 | BOPP | PVDC, two sides |
| 8 | BOPP | PVDC, one side |
| 9 | BOPP | PVDC one side + Acrylic one side |
| 10 | Matte BOPP | PVDC, one side |
| 11 | Heat-sealable BOPP | PVDC, one side |
Not in the list? Coating weight, base-film gauge and roll width are all adjustable. If your structure needs a configuration outside these eleven, send the specification and we will confirm feasibility before quoting.
Which base film
The coating decides the barrier. The base decides everything else — stiffness, temperature window, seal behaviour and cost — and choosing the base wrong is more expensive than choosing the coating wrong.
BOPP is the cheapest of the three and accounts for six of the eleven configurations above. It also has the lowest temperature resistance, so it suits overwrap, labels and dry goods rather than anything that sees heat. A heat-sealable grade lets you run a coated structure with no separate sealant ply at all, which is the cheapest route to a one-ply barrier pack.
BOPET carries more stiffness and a wider temperature window than BOPP, and it prints cleanly. Where the pack needs a board-like feel or has to hold its shape on shelf, this is usually the base. It costs more per square metre, and it is not a seal layer — a PE or cast-PP ply still has to be added.
BOPA (nylon) is specified for mechanical reasons, not barrier reasons: puncture resistance, flex resistance and the ability to hold a vacuum. Coated BOPA is the standard choice for vacuum packs and for contents with sharp edges or real weight. It costs the most of the three and is rarely the only ply.
A short way to hold it: BOPP when cost decides, BOPET when stiffness and heat decide, BOPA when the pack has to survive.
What coated films give you
- Barrier performance — moisture, oxygen, aroma and gas, in one thin functional layer
- Scratch and abrasion resistance — a hard coat protects the print underneath
- Durability and flexibility — the coating does not embrittle the base film
- Printability — clean ink adhesion without pre-treatment surprises
- Heat sealability — including dedicated heat-sealable BOPP grades
Typical converting routes
| Route | Typical end use |
|---|---|
| Overwrapping | Boxes, cartons, confectionery |
| Vertical & horizontal form-fill-seal | Snacks, powders, dry foods |
| Printing | Surface-printed barrier packs |
| Lamination | Two- and three-ply barrier structures |
| Washing-machine labels | Durable, moisture-resistant label stock |
| Bakery, biscuits, confectionery, dairy, meat | Direct food-contact packaging |
| Window glass and panes | Protective and decorative surfacing |
What the coating has to survive
A coating is a surface. Everything that touches that surface in converting and filling acts on the barrier, and three of those actions matter more than a datasheet suggests.
The seal area. Heat and pressure close the pack, and they also compress whatever sits in the seal zone. This is why a single-side coating normally goes on the outside face, away from the seal. If you are specifying two-side PVDC, confirm which face runs to the sealant before the trial — reversing it removes barrier from the seal without changing anything visible.
Flex and fold. Coated films crack under repeated flexing, and the crack is invisible until the barrier is tested. On a flat bag this rarely matters. On a stand-up pouch, the base folds take the most flexing and they are where a coated structure is most likely to fall short of its flat-film number.
Abrasion before filling. Coating weight is set to survive the printer, the laminator and the filler — not just the trip to your door. A high-friction print stack or a tight web path can scuff the coating before the pack is ever formed. If your line has not run coated stock before, trial a short length rather than a full container.
None of this argues against coated film. It argues for testing on your machine rather than on a datasheet — which is why we send a sample roll before quoting volume.
Why buyers shortlist OLUNRO
- In-house coating, metallizing, lamination and slitting. Structure changes are a shop-floor decision, not a supplier negotiation.
- Eleven standard configurations, plus custom. You are not pushed into a catalogue item because it happens to be in stock.
- Processability confirmed before volume. Tell us the machine and the sealing conditions; we confirm the roll runs before you commit to a container.
- Batch-to-batch consistency. The same coating line, the same operators, the same slitting tension — so run twenty behaves like run one.
Request a coated film sample
Send us the base film, the barrier target and your converting route — VFFS, HFFS, overwrap or lamination — and we will come back with the recommended coating configuration, a specification sheet and a sample roll for your own trials.
Contact: info@olunropack.com · +86 532 6776 6956