Metallised film

Metallised films (or metallized films) are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost. Metallised films are widely used for decorative purposes and food packaging, and also for specialty applications including insulation and electronics.

Manufacture

Metallisation is performed using a physical vapor deposition process. Aluminium is the most common metal used for deposition, but other metals such as nickel and chromium are also used. The metal is heated and evaporated under vacuum. This condenses on the cold polymer film, which is unwound near the metal vapour source. This coating is much thinner than a metal foil could be made, in the range of 0.5 micrometres.^[1] This coating will not fade or discolour over time. While oriented polypropylene and polyethylene terephthalate (PET) are the most common films used for metallisation, nylon, polyethylene and cast polypropylene are also used.^[2]

Properties

Metallised films have a reflective silvery surface similar to aluminium foil and are highly flammable. The coating also reduces the permeability of the film to light, water and oxygen. The properties of the film remain, such as higher toughness, the ability to be heat sealed, and a lower density at a lower cost than an aluminium foil. This gives metallised films some advantages over aluminium foil and aluminium foil laminates. It was once thought that metallised films would become a replacement for aluminium foil laminates, but current films still cannot match the barrier properties of foil. Some very high barrier metallised films are available using EVOH, but are not yet cost effective against foil laminates.^[3]

Comparison of Metallised PET and aluminium foil
	Moisture (g/m²·day)	Oxygen (mL/m²·day)	UV light (%transmittance)
PET film, 12.7 μm^[1]	31	465	91
Metallised PET^[1]	0.8	1.2	5
Aluminium foil 6 μm^[4]	0	0	0

Uses

Decoration

Metallised films were first used for decorative purposes as Christmas tinsel,^[1] and continue to be used for items such as wrappers, ribbons, and glitter. Metallic helium-filled novelty balloons given as gifts are made of metallised BoPET and often called Mylar balloons commercially.

Packaging

Both metallised PET and PP have replaced foil laminates for products such as snack foods, coffee and candy, which do not require the superior barrier of aluminium foil. Metallised nylon and polyethylene are used in the meat export market. The controlled permeation extends shelf life.

Metallised films are used as a susceptor for cooking in microwave ovens.^[5] An example is a microwave popcorn bag.

Many food items are also packaged using metallised films for appearance only, as these produce a package with greater sparkle when compared to competing products that use printed paper or polymer films.

Insulation

Metallised PET films are used in NASA spacesuits to reflect heat radiation, keeping astronauts warm, and in ″proximity suits″ used by firefighters for protection from the high amount of heat released from fuel fires. Aluminized emergency blankets ("space blankets") are also used to conserve a shock victim's body heat. MPET has been used as an antistatic container for other heat and sound insulating materials used in aircraft, to prevent the insulation from leaking into the passenger cabin, but is not itself the insulator in that use. Burning MPET insulation was identified as a cause of the crash of Swissair Flight 111 in 1998 that killed 229 people, leading to new recommendations on its use in airliners.

Electronics

Metallised films are used as a dielectric in the manufacture of a type of capacitor used in electronic circuits,^[6] and as a material in some types of antistatic bags.

References

^ ^a ^b ^c ^d Hanlon, J. (1992). 1st ed. Handbook of Package Engineering, Lancaster, PA, Technomic Publishing: ISBN 0-87762-924-2. Chapter 4 Coatings and Laminations
^ Mount, E. (2004) Metalized Films for Food Packaging, Converting Magazine vol 3
^ Mount, E. (2002) Metalized Film Barriers: Where to Next? Converting Magazine vol 3
^ European Aluminium Foil Association Archived 2007-08-03 at the Wayback Machine
^ Sun, Da-Wen (2016-04-19). Handbook of Frozen Food Processing and Packaging, Second Edition. CRC Press. ISBN 9781439836057.
^ Pardos, Françoise (2004). Plastic Films: Situation and Outlook : a Rapra Market Report. iSmithers Rapra Publishing. ISBN 9781859574805.

v t e Packaging
General topics	Active packaging Child-resistant packaging Contract packager Edible packaging Modified atmosphere/modified humidity packaging Overpackaging Package delivery Package pilferage Package testing Package theft Packaging engineering Resealable packaging Reusable packaging Reuse of bottles Shelf life Shelf-ready packaging Shelf-stable Sustainable packaging Tamper-evident Tamper resistance Wrap rage
Product packages	Alternative wine closure Ammunition box Banana box Beer bottle Box wine Case-ready meat Coffee bag Cosmetic packaging Currency packaging Disposable food packaging Drink can Egg carton Evidence packaging Field ration Flour sack Foam food container Food packaging Fuel container Gas cylinder Glass milk bottle Growler Juicebox Low plastic water bottle Luxury packaging Milk bag Optical disc packaging Oyster pail Popcorn bag Pharmaceutical packaging Plastic milk container Purdue Improved Crop Storage bags Sand bag Seasonal packaging Self-heating food packaging Screw cap (wine) Single-serve coffee container Spray paint Toothpaste pump dispenser Unit dose Water bottle Wine bottle
Containers	Aerosol spray dispenser Aluminium bottle Aluminum can Ampoule Antistatic bag Bag-in-box Bag Barrel Biodegradable bag Blister pack Boil-in-bag Bottle Box Bulk box Cage Case Carboy Carton Chub Clamshell Corrugated box design Crate Disposable cup Drum Endcap Envelope Euro container Flexible intermediate bulk container Flexible tank Folding carton Glass bottle Gunny sack Inhaler Insulated shipping container Intermediate bulk container Jar Jerrycan Jug Keg Mesh bag Multilayered packaging Multi-pack Packet (container) Padded envelope Pail Paper bag Paper sack Plastic bag Plastic bottle Retort pouch Salvage drum Sachet Water sachet Security bag Shipping container Shipping tube Skin pack Spray bottle Squround Stand-up pouch Steel and tin cans Tetra Brik Thermal bag Tub (container) Tube Unit load Vial Wooden box
Materials and components	Adhesive Aluminium foil Bail handle Bioplastic Biodegradable plastic BoPET Bubble wrap Bung Cellophane Closure Coated paper Coating Coextrusion Container glass Corrugated fiberboard Corrugated plastic Cushioning Desiccant Double seam Flip-top Foam peanut Gel pack Hot-melt adhesive Humidity indicator card Kraft paper Label Lid Linear low-density polyethylene Liquid packaging board Living hinge Low-density polyethylene Meat absorbent pad Metallised film Modified atmosphere Molded pulp Nonwoven fabric Overwrap Oxygen scavenger Package handle Packaging gas Pallet Paper Paper pallet Paperboard Plastic-coated paper Plastic film Plastic pallet Plastic wrap Polyester Polyethylene Polypropylene Pressure-sensitive tape Pump dispenser Screw cap Screw cap (wine) Security printing Security tape Shock detector Shock and vibration data logger Shrink wrap Slip sheet Staple (fastener) Strapping Stretch wrap Susceptor Tamper-evident band Tear tape Temperature data logger Time temperature indicator Tinplate Velostat
Processes	Aseptic processing Authentication Automatic identification and data capture Blow fill seal Blow molding Calendering Canning Coating Containerization Converting Corona treatment Curtain coating Die cutting Die forming (plastics) Electronic article surveillance Extrusion Extrusion coating Flame treatment Glass production Graphic design Hazard analysis and critical control points Hermetic seal Induction sealing Injection moulding Lamination Laser cutting Molding Package tracking Papermaking Plastic extrusion Plastic welding Printing Product development Production control Quality assurance Radio-frequency identification Roll slitting Shearing (manufacturing) Thermoforming Track and trace Ultrasonic welding Vacuum forming Vacuum packaging Verification and validation
Machinery	Barcode printer Barcode reader Bottling line Calender Can seamer Cap torque tester Cartoning machine Case sealer Check weigher Conveyor system Drum pump Extended core stretch wrapper Filler Heat gun Heat sealer Industrial robot Injection molding machine Label printer applicator Lineshaft roller conveyor Logistics automation Material-handling equipment Mechanical brake stretch wrapper Multihead weigher Orbital stretch wrapper Packaging machinery Pallet inverter Palletizer Rotary wheel blow molding systems Seed-counting machine Shrink tunnel Staple gun Tape dispenser Turntable stretch wrapper Vertical form fill sealing machine
Environment, post-use	Biodegradation Can collecting Closed-loop box reuse Environmental engineering Glass recycling Industrial ecology Life-cycle assessment Litter Packaging waste Paper recycling PET bottle recycling Plastic recycling Recycling Reusable packaging Reverse logistics Source reduction Sustainable packaging Waste management
Category: Packaging