FIBRE BOTTLES

At the end of last year, the paperindustry met in Brussels to celebratethe 25th anniversary of the Confeder-

ation of European Paper Industries (CEPI).This ‘grand messe’ was full of speeches abouttrends and forecasts but also innovation, suchas the ongoing Green Fibre Bottle cooperativeproject.

As information is scarce on this project, itwas opportune that Plastics in Packaging wasalso there, as it provided an insight into howmuch of a challenge this technology can poten-tially provide to plastics packaging.

In 2010, Jesper Servé, founder and chiefexecutive of SME ecoXpac, and Soren Ostegaard,head of packaging at the Danish TechnologyInstitute, got together with the objective tomanufacture a fully biodegradable bottle. TheCarlsberg group showed almost immediateinterest so that it could package its beer inwhat was a revolutionary bottle.

The claim was bold: The Green FibreBottle could replace plastics and glass bottlesby using only moulded paper pulp. Its end oflife is said to be straightforward, as the bottlewill naturally biodegrade or be recycled alongwith other paper-based products. But the pro-duction of a cellulose-fibre bottle is far fromeasy and the challenges are numerous. Twoadditional research centres joined the effort:CTP, the French Paper Technical Center andDTU, the Danmarks Tecknishe Universiteit.

To enhance the environmental footprintand sustainability of the bottle, the consortiumcreated what it calls “an energy efficient man-ufacturing process”. An innovative way ofdrying the products, called Impulse Drying,was adopted. In seconds, this process removesa large amount of water from the wet pulpwith a combination of mechanical pressure (30to 50 bar) and a high temperatures (200-400deg C). It reduces the drying/forming timefrom around two minutes to less than six sec-onds.

The process requires turning the surfacemoisture of the pulp fibre to steam, and thenreleasing a vacuum on the other side of themould tool to allow the stream to expel themoisture from the pulp.

Dual layer of biodegradable coatingsMoulded paper pulp lacks a barrier againstliquids and gases. In theory, cellulose fibrewith a silicon oxide coating is a moderatelyporous material, but in practice that cellulosefibre with silicon oxide leaves pores of around1-10 microns open. The coating smooths outthe surface inherently rough at microscopicscale due to the size of the cellulose fibres. Thesilicon oxide is deposited by plasma andenhanced by chemical vapour deposition.

The intermediate layer enables the cellulose

Technologyin a bottle

How do the sustainability credentials and functionality of the Green FibreBottle stack up? Dominique Huret provides an update

How do the sustainability credentials and functionality of the Green FibreBottle stack up? Dominique Huret provides an update

20 Plastics in Packaging © 2018 Sayers Publishing Group • March

Have all technicalchallenges of the fibre bottle been overcome?

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Plastics in Packaging © 2018 Sayers Publishing Group • March 21

to be fully liquid repellent. This barrier layeris starch-based, uses sorbitol as plasticiserand nano clay or micro-fibrillated cellulose asfillers. Citric acid does the crosslinking job ofthe particles.

With these two layers, the gas barrierproperties are comparable to those of oil-basedpolymers of similar thickness, says the consor-tium.

Because a beer is best chilled… The outer surface of a bottle gets wet when it isfilled with a chilled liquid because watervapour condenses on it out of the surroundingair.

To solve this in an environmentally friendlyway on the Green Fibre Bottle, an innovativechemical process was patented by CTP andCNRS (the French research centre) calledChromatogeny. This solvent-free grafting processbrings hydrophobicity and high repellency tothe outer walls using ultra-fast technology forR2R process. It brings resistance while keepingrecyclability and biodegradability.

At the Davos World Forum in 2015, Carls-berg’s chief executive made a bold announcementabout the green bottle and showcased aprototype design. It is not a surprise thatCarlsberg would pioneer such a bottle, as the

Danish firm was also an early user of polyeth-ylene naphthalate (PEN) bottles about a decadeago (Plastics in Packaging, February 2017).

Two years on and most technical challengesassociated with the fibre bottle are said tohave been overcome. The bottle cap seems toremain an obstacle, however, since it also

needs barrier functionalities. These bottle technologies are all well and

good if, at the end, the beer is chilled and fizzyfor the consumer. Whether the green fibrebottle will ever present a valid challenge to aPET barrier bottle, meanwhile, remains to beseen.

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Whether it is inhouse, post-consumer or bottle recycling: you can only close loops in a precise and profi table way if machines are perfectly tuned for the respective application. Count on the number 1 technology from EREMA when doing so: over 5000 of our machines and systems produce around 14 million tonnes of high-quality pellets like this every year – in a highly effi cient and energy-saving way.

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Carlsberg was an earlypioneer of a ‘green’ fibrebottle

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