Multilayer Packaging Films details sector advances

An Applied Market Information product story

Edited by the Processingtalk editorial team Dec 24, 2008

Food packaging is the main application for film, comprising 74 per cent of the market, according to Andrew Reynolds, research director at Applied Market Information (AMI).

Of this, roughly 12 per cent is used in each of the following sectors: bakery, dried foods, confectionery, dairy and meat.

Reynolds was speaking at Multilayer Packaging Films 2008, which took place in November in Cologne.

Windmoller and Holscher has outlined the properties of the materials commonly used in layered films: polyethylene is used for sealing and as a water vapour barrier; polypropylene provides mechanical properties and water vapour barrier; polyamide offers aroma- and oxygen-barrier with stiffness; EVOH offers high oxygen barrier; EVA is good for sealing; while mLLDPE gives good optical and mechanical properties.

Active and intelligent packaging systems are a focus of the Klockner Pentaplast Group.

For example, a film can include an oxygen-scavenging layer and a fresh fruit packaging film can have an ethylene-absorbing layer to slow the ripening process.

Antimicrobial packaging is growing outside Europe and thermochromic materials are being tested to give a colour indicator when packages are at the correct temperature.

Amcor Flexibles produces a range of laminates using materials such as PVDC and EVOH, with high barrier properties to a range of substances including oxygen, water vapour, carbon dioxide, fats and aromas.

There are sealable and printable grades.

Innovia Films has produced a Natureflex bioplastic-based film with good gas and moisture barrier properties - previously very difficult to achieve with biodegradable materials.

One application is in sweet wrappers for Quality Street.

FKuR Kunststoff offers expertise in compounding bioplastics so that they can be used on conventional equipment.

The Bioflex-A series is a PLA blend for blown film extrusion and has been used in multilayer films.

Mitsubishi Plastics has introduced a silicone dioxide vacuum coated layer to give high barrier to oxygen and water.

OPET and OPA are used as base films.

It is protected by an additional layer to permit printing, and so on.

Cyclic olefin copolymers from Topas can be metallised to give high barrier films with high stiffness, excellent hot tack and controlled tear.

BASF supplies polyamide (Ultramid range) for multilayer films and has expertise in factors such as viscosity matching of PE and PA to give uniform layer distribution.

Biaxially oriented PA provides high stiffness, high strength and puncture resistance.

Sabic has carried out research on polyolefins for five-layer coextruded film structures to achieve 20 per cent downgauging for applications such as diaper packaging and beverage collation shrink-wrapping.

Dow has a core range of copolymer polyolefin materials for sealing layers.

Nippon Gohsei produces high gas barrier ethylene vinyl alcohol copolymer (EVOH) with good processability.

It also has a grade for shrink film where PVDC is more commonly used as it has high barrier properties combined with high shrinkability.

DSM supplies polyamide and also adhesive layers: Yparex is a maleic anhydride modified polyolefin.

It has been tested as an interlayer for PE and PA/EVOH, PE and metals, and PP and PA/EVOH.

The overall film structure is usually: barrier layer, adhesive layer, sealing layer.

Fabes is developing test methods to predict migration from multilayer films.

Keller and Heckman specialises in legal aspects of food packaging safety: printing inks and coatings are not yet covered by positive lists and are treated as plastics.

Producers have to demonstrate compliance and often have to reassure customers about the latest scare stories in the media from BPA to melamine.

Davis Standard has been working on ways of reducing costs and waste in multilayer film production including encapsulation of the layered section with a monolayer trim of polyolefin, which means that the trim can be recycled.

Polyamide-polyethylene film curls during crystallisation; this can be reduced by using PA with lower crystalline content or adding other layers.

Reifenhauser Extrusion supplies cast film lines into this market and Extrusion Dies Industries is working on layer multiplication using multiple feedblocks and three manifold die.

Quality control equipment is supplied by Isra Vision (using multiple line cameras) and Honeywell using full spectrum infrared equipment.

Specialty film is developing in terms of technology and markets.

Use of barrier films prevents a massive amount of food waste each year.

The next industry forum, Multilayer Packaging Films 2009, will be held on 16-18 November 2009 at the Maritim hotel in Cologne, Germany.