Polyester Packaging Film (PET)

What is Polyester Film?

Polyester film - known in the industry as PET or BOPET (Biaxially Oriented Polyethylene Terephthalate) - is a high-performance packaging material that outperforms most alternatives on barrier properties, temperature resistance, and optical clarity.

Where BOPP is the everyday workhorse of flexible packaging, PET is what you reach for when you need more. More barrier. More temperature resistance. More strength. It costs more than polypropylene films, but for applications where performance matters, PET justifies the premium.

You’ll find PET film sealing ready meal trays, providing windows in sandwich cartons, wrapping products that need to survive the microwave or oven, and forming the outer layer of high-barrier laminates. It’s the film that handles the jobs other materials can’t.

Why Choose Polyester?

Temperature Performance

PET maintains its properties from -70°C to +220°C. This means a single packaging solution can handle the journey from production through frozen storage, chilled distribution, and cooking - whether microwave or conventional oven.

For ready meals in CPET trays, PET lidding film lets consumers take the pack straight from fridge to oven without repackaging. That’s convenience that sells.

Oxygen Barrier

PET’s oxygen barrier is significantly better than BOPP or CPP. Where standard BOPP transmits 93-300 cc/m²/24hr, PET transmits just 1.8-7.7 cc/m²/24hr. For oxygen-sensitive products - anything that goes stale, rancid, or loses flavour on exposure to air - this difference translates directly to extended shelf life.

Add metallisation or PVDC coating and the barrier improves further, approaching the performance of aluminium foil laminates while remaining transparent or semi-transparent.

Clarity and Strength

PET offers exceptional optical clarity - better than BOPP in most grades. Combined with high tensile strength and puncture resistance, it’s the natural choice for carton windows where you need to see the product clearly while protecting it from handling damage.

Types of Polyester Film

Heat-Sealable PET

Co-extruded with a sealant layer that bonds directly to tray materials without additional adhesives. This is what we use for lidding films - sealing to APET, CPET, rPET, PP, and other tray substrates.

Available in peel seal (for consumer-friendly opening) and weld seal (for tamper evidence or economy) formulations. Anti-fog treatments keep products visible in chilled cabinets.

Metallised PET

A microscopic layer of aluminium deposited on the film surface through vacuum metallisation. This transforms PET’s already-good barrier properties into excellent:

	Standard PET	Metallised PET
Oxygen barrier	1.8-7.7 cc/m²/24hr	Less than 0.1 cc/m²/24hr
Moisture barrier	16-20 g/m²/24hr	Less than 1 g/m²/24hr
Light barrier	Transparent	Opaque

Metallised PET is used in laminate structures for snacks, confectionery, and products requiring extended shelf life with an attractive metallic finish.

PVDC-Coated PET

PVDC (polyvinylidene chloride) coating adds a high-performance barrier layer while maintaining transparency. Oxygen transmission drops to 0.3-0.5 cc/m²/24hr - not quite as low as metallised, but you retain the ability to see the product.

Used for pharmaceutical packaging, high-value foods, and applications where both barrier and visibility matter.

Plain/Corona-Treated PET

Standard PET without heat-seal coating - used as a print surface in laminate structures or where adhesive lamination is preferred. Corona treatment increases surface energy for ink adhesion and lamination bonding.

Applications

Lidding Films

PET is the dominant material for tray lidding in chilled and ambient food. Heat-sealable grades bond reliably to APET, CPET, rPET, PP, PE, aluminium, and paperboard trays.

We supply lidding films for ready meals, prepared salads, deli items, meat and poultry, and fresh produce. Peel seal for consumer-friendly opening, weld seal for tamper evidence. Anti-fog treatments for chilled display.

For ovenable applications, PET lidding on CPET trays handles conventional ovens up to 220°C.

Window Patch Film

Crystal-clear PET provides windows in sandwich cartons, bakery boxes, and retail packaging where consumers want to see what they’re buying. The film’s strength prevents punctures from handling, while its clarity shows products at their best.

Flow Wrap

Where temperature resistance or barrier properties exceed what BOPP can deliver, PET flow wrap is the alternative. Baked goods going into warm packs, products requiring better oxygen barrier, applications where film needs to survive thermal processing.

Ovenable Bags and Sheets

We convert PET into bags and sheets for oven-ready applications. Roasting bags, cook-in pouches, interleaving sheets for products that will be reheated. Temperature resistance to 220°C means the packaging handles whatever the oven delivers.

Laminate Structures

PET frequently forms the outer layer of laminate structures - printed surface facing out, with metallised film or other barrier layers inside. The combination delivers both presentation and protection.

Common structures include PET/metallised PET, PET/aluminium foil/PE, and PET/EVOH/PE for high-barrier applications.

PET vs Other Films

	PET	BOPP	CPP
Oxygen barrier	Excellent	Moderate	Poor
Moisture barrier	Moderate	Good	Good
Temperature range	-70°C to +220°C	-20°C to +105°C	-20°C to +135°C
Clarity	Excellent	Excellent	Good
Stiffness	High	High	Low
Heat sealable	With coating	Co-extruded	Yes
Cost	Higher	Lower	Lower

Choose PET when you need temperature resistance, oxygen barrier, or both. Choose BOPP for general-purpose packaging where cost matters more than barrier. Choose CPP when you need flexibility and tear resistance.

Thickness Guide

	Typical Applications
12μm	Lightweight lidding, carton windows, laminate layers
19μm	Economy lidding, window patch
23μm	Standard lidding, flow wrap
36μm	Heavy-duty applications, enhanced barrier

Thicker film provides better barrier and mechanical properties but at higher cost. We can advise on the minimum gauge that delivers reliable performance for your application.

Printing on Polyester

PET accepts both flexographic and gravure printing on corona-treated surfaces. The film’s dimensional stability means excellent registration - graphics stay sharp and aligned across long runs.

We print up to 4 colours in-house and up to 10 colours through our print partners. The high clarity and gloss of PET make printed graphics pop - colours appear more vivid than on most other substrates.

Recyclability

PET is resin code #1 - the most widely recycled plastic with established collection and reprocessing infrastructure worldwide. Unlike multi-material laminates that require specialised recycling, PET film can be processed through conventional PET recycling streams.

Mono-material PET packaging (like PET lidding on PET trays) qualifies for OPRL “Widely Recycled” labelling in the UK. This matters for brands and retailers under pressure to improve packaging recyclability.

We can supply films with post-consumer recycled (PCR) content for customers working toward Plastic Packaging Tax thresholds or corporate sustainability targets.

What We Supply

We stock heat-sealable PET in common gauges for quick dispatch. Metallised and coated grades are made to order.

All conversion is done in-house at our UK facility:

• Slitting to your required width
• Sheeting for flat applications
• Bagmaking for ovenable bags and pouches
• Printing up to 10 colours

For lidding film specifically, see our dedicated lidding films page which covers seal types, tray compatibility, and barrier options in detail.

Working With Us

We’re a family-owned UK converter with four decades of experience in flexible packaging. If you’re not sure which PET grade suits your application, give us a call. We’ll talk through your requirements - temperature exposure, barrier needs, seal type, tray material - and recommend the right specification.

For large or ongoing requirements, our stockholding service lets you secure pricing and availability while calling off smaller quantities as needed.