From farm to finished product

Of the 85,000 hectares of European land currently estimated to be growing flax, France has 68,000 hectares (80%), of which the region of Normandy holds a 55% share of French production, or 37,400 hectares.

Flax belongs to the bast class of natural fibres which also includes hemp, jute, kenaf and bamboo. After having been almost completely replaced by their synthetic counterparts in the 1960’s and 1970’s, bast fibres have rapidly regained ground since the 1990s – especially in automotive applications.

In Europe, around 40,000 tonnes of bast fibres are used each year in compression moulded composites – usually needlepunched or airlaid nonwoven mats impregnated with resin and hardened by a combination of pressure and heat curing – with 95% of current applications in automotive, and the remainder in luggage.

This is predicted to rise to 120,000 tonnes by 2020. A further 100,000 tonnes employ cotton fibre-based materials for use mainly in truck parts, but little growth is seen here.

Pioneer

Bast-based nonwovens have been pioneered by companies like EcoTechnilin, which is a UK-owned company but has its needlepunched nonwoven plant located in the flax fields of northern France.

EcoTechnilin is currently producing over 4,500 tonnes of nonwovens annually and has been supplying these materials to the car industry for over 20 years.

Well-established applications involve flax/PP resin ‘prepregs’, which are thermo-compressed by automotive Tier 1 suppliers into door trims, trunk trims, seat backs and instrument panels.

Bio-sourced

For the past five years EcoTechnilin has been developing a range of bio-sourced prepregs which combine its 100% flax nonwovens with a fast-curing, sugar-based bioresin.

The flax fibres employed are the shorter, cheaper co-product of the long flax fibres that go into the linen industry, while the resin is produced from a co-product of sugar production in which the non-edible waste is transformed into a water-based resin.

As a consequence, both the nonwoven and the resin within EcoTechnilin bio-sourced prepregs have excellent Life Cycle Assessment (LCA) results, with very low environmental impact. As a bonus, curing times are less than 50 seconds for single thickness panels and 150 seconds for sandwich materials.

The first two bio-sourced composite applications to be industrialised are a paper-honeycomb sandwich material (FibriCard, now in production in a load floor at Jaguar Land Rover), and a single thickness ceiling tile (FibriBoard FR, developed with a large US ceiling tile producer).

The latest development from this company is FibriRock, which has already claimed a number of industry awards.

It combines a flame-resistant flax/ bioresin nonwoven prepreg similar to a version developed for ceiling tiles. It has a woven basalt reinforcement which, when used with a Nomex-type core, results in a very rigid composite with excellent fire/smoke performance and fast processing times of less than 150 seconds.

The product is suitable for aircraft and rail applications and is first going into production in 2015 in a lightweight galley cart.

Aircraft seats

Zodiac Aerospace, meanwhile, headquartered in Plaisir, France, is currently in the process of moving from composites made of glass fabrics and phenolics to flax-based nonwoven materials for the frame structures of its Premium and Business Class aircraft seats.

The aircraft interiors specialist – which achieved sales of €4.2 billion in its 2013/14 financial year – has been developing composites based on Twinflax, a flax fabric reinforcement, as part of the Fiabilin Project.

The Fiabilin Project involves Zodiac Aerospace subsidiary C&D Addler and a range of suppliers who belong to the FiMaLin consortium in the Normandy region.

The aim of FiMaLin is to establish good practices in technical flax management ensuring both the definition of technical specifications and the establishment of specification sheets to meet industry needs, amongst others.

The entire supply chain for the Zodiac Aerospace materials – from farm to finished component – has been developed by the FiMaLin companies as part of the Fiabilin Project.

Conversion

A number of regular exhibitors at INDEX  – the leading nonwovens show which next takes place at the Palexpo from 4th-7th April 2017 – specialise in the technology for the conversion of natural fibres such as flax into highly effective nonwoven products.

They include Italian companies Bematic, Bombi and Cormatex, along with Laroche of France. The technologies of other leading machinery builders such as Andritz, Autefa, DanWeb, Dilo, M&J and Trützschler are also be engineered specifically to process natural fibres.

And flax is certainly not the only natural fibre finding its way into such applications.

At the last INDEX show in 2014, Cormatex, who are based in Montemurlo, Prato, Italy, displayed a wide range of materials produced on its airlaying machines.

In addition to flax, these include processed jute, sugarcane, coconut fibre and regenerated cotton in a very broad weight range of from 150 gsm up to 3,000gsm.

Applications for the products made on these machines include automotive preformed panels, seat wadding, soundproofing and thermal insulation materials, furnishing products such as sofa, mattress and chair waddings, bed quiltings and sleeping bags, roof and wall insulation materials, packaging, interlinings and sanitary articles.

Meanwhile, over the years, airlaying – in which short-cut staple fibres are dispersed in air and bonded by combinations of friction, cohesion or adhesion – has also been successfully employed to consolidate nonwovens from a wide range of other raw materials, including:

• Rice straw remains
• Waste from wood/leaves
• Orange peel
• Corn straw
• Tea leaves
• Leather remains/waste
• Train tickets
• Newspapers

While it is unlikely that any of these materials will make much of an impact on mass markets, they certainly serve to illustrate the versatility of nonwoven technologies. This is hardly surprising, given the vast range of fibres – both natural and synthetic – that are already employed, and the diverse end-use markets to which nonwovens are supplied.

You will find this amply showcased at INDEX™17.

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