Are the Days of Petrochemical-Based Nonwovens Numbered?

Tag : PP Spunbond Nonwoven

The growth of the biodiesel industry meanwhile, has resulted inmore polymers from biomass, according to Polymers from Biomass, thelatest report by SRI Consulting (SRIC).
There are many ways to obtain biopolymers, the report states.Polyethylene, for instance, is being produced from sugar cane viafermentation to ethanol, which can be dehydrated to ethylene.
The burgeoning production of biodiesel has yielded large amounts ofthe by-product glycerin, much of which is looking for a market. Oneof these markets, for example, is converting glycerin intoepichlorohydrin, which is used to manufacture epoxy resins.
The report's author Bob Davenport says "Biomass derived polymersthat are biodegradable include polylactic acid (PLA) andpolyhydroxyalkanoates (PHAs). These bioderived polymers are notnew, but only recently have seen markets develop into commercialvolumes."
The report examines various monomers and co-monomers that can beproduced from biomass, polymers derived directly from biomass andcellulosic polymers, as well as monomers formerly produced frompetrochemicals that can be produced from biomass sources.
Like petroleum-derived products, bio-derived polymers can be usedas fibres, films or engineering resins.
"Many factors are driving the use of biomass-derived polymers,"adds Davenport."These include sustainability, domestic sourcing ofraw materials that are annually reproduced, using materials andprocesses that are low on greenhouse gas emissions, and employinglocal farms and labour."
In manufacturing, biopolymers must perform economically andefficiently in their applications.
Whereas ethanol-based ethylene only faces the economic hurdle, manyof the new polymers also face performance standards in theirdeveloping markets.
DIFFERENTIAL
General Manager of nonwovens industry body EDANA, Pierre Wiertz,says "Polymers derived from renewable sources that can be used toproduce compostable plastics have been available in limitedquantities for many years and have generally been used to produceplastic films for use in packaging and organic waste disposalapplications. These films can also be used in absorbent hygieneproducts, but there is currently a cost differential betweenpolyolefin resin and resin derived from these polymers of a factorof one to three.
"In a cost sensitive market such as absorbent hygiene products thispresents a significant barrier" he adds. "Currently cost andavailability restrict the use of such materials to absorbenthygiene products within low volume, specialized niche markets. Thismay well change, however, as availability increases and economiesof scale emerge. More recent developments have seen the emergenceof fibres made from polymers from renewable sources. Such fibrescan be used in nonwoven applications and providing there iseconomic fibre supply these could be interesting developments forthe future, which the absorbent hygiene products industry ismonitoring.
"The environmental impact of such polymers must be measured by acomplete cradle-to-grave life cycle assessment approach. The factthat they are derived from renewable resources does notautomatically mean that they are better for the environment. Allenergy consumption and emissions occurring in the productionprocess and its conversion into a substrate need to be considered.
"The broader sustainability issues surrounding these polymers arecomplex and include the [carbon dioxide] CO2 emissions that occurin the degradation of biodegradable materials, the ethics of usingfood crops, and the use of arable land to grow precursormaterials." SAFETY TOO
"New materials must also be assessed in terms of their safetyprofile and their performance to ensure that there is nodeterioration in either the performance or the safety of the finalproduct, compared with those produced using existing materials."
"The absorbent hygiene product industry will continue to monitoropportunities to use sustainable alternatives to fossil fuel-basedresource, while continuing to reduce the amount of material in itsproducts, which is currently the most effective way to minimizetheir environmental impact."
CELLULOSICS
Cellulosic fibres are very likely to have a larger role in thefuture of nonwovens, which is good news particularly for Austria-headquartered Lenzing.
Nonwoven fabrics made from Lenzing's Viscose and Tencel fibres havebeen certified and registered as compostable materials by DinCertco, the certification organization of TUV Rheinland Group andthe German Institute for Standardization (DIN).
Lenzing fibres are fully biodegradable, and unlike fossil fuel-based types decompose completely in soil burial or sewage treatmentplants.
Lenzing is actively promoting the eco benefits of its fibres.
They are converted into pure water and CO2 which are reabsorbedduring photosynthesis of green plants and converted into cellulose.In the past two years, massive expansions in viscose production andthe pulp required to produce it have been announced-totalling inexcess of half a million tonnes of new fibre'.
In the absence of this new capacity, viscose and lyocell priceshave risen sharply and the market has been undersupplied due tohigh demand in textiles as well as nonwovens. Lenzing, notsurprisingly, had a record year for fibre production in 2007 withits output reaching 560 kt, compared with 480 kt in 2006, mainly asa result of the start of production at a new plant in Nanjing,China(ii).
Research into cellulose and its derivatives is also increasing andincludes work on the processes potentially capable of manufacturinglow cost cellulosic nonwovens.
ABUNDANT
Consultant Calvin Woodings believes cellulosics have a strongchance of replacing polypropylene as the workhorse fibre fordisposable nonwovens: "Cellulose is the only really abundant fibre-forming polymer produced and disposed within the carbon cycle" hesays."Pure cellulose in the form of cotton, grown organicallymaybe, has the least environmental impact of any fibre and would bea low- cost yet valuable crop.
"Numerous processes exist for making cellulosic fibres frombiomass, and all are potentially carbon-neutral because the partsof the biomass unsuitable for including in the finished fibres canbe used to power the pulping, dissolution and fibre spinningoperations."
Currently, existing nonwoven processes can convert these fibresinto nonwovens, provided hydroentanglement is the bonding system.Cellulose can also be spunbonded in various ways to make self-bonded nonwovens or spunlaid.
"Assembling finished disposables without the help ofthermoplasticity would be tricky" Woodings adds "but fabrics can beglued or even stitched together - by computercontrolled highpressure water needles - in the same way as these needles, at evenhigher pressure, are used as cutters."
Cellulosic fibres can also be converted into superabsorbents andsuch products are already used in wound care.
"Cellulosic disposables would be fully compatible with sewagesystems, especially if the fibres are short and lightly bonded, orif the products are shredded through a waste disposal unit attachedto the toilet" Woodings concludes. "Maybe as new infrastructure isdeveloped and old infrastructure renewed, the installation of thisoption would take a load off landfill and reduce the environmentalcosts of collecting and transporting rubbish from homes to landfillor aerobic composters."
FiberVisions continues to expand its production of a variety ofheavily-engineered bicomponent fibres.
BICOMPONENTS
One company seemingly unperturbed by all this is ES Fibervisions,which has just installed its thirteenth dedicated bicomponent fibreline at its European production site in Varde, Denmark, also itslargest to date.
The latest line expands the production and supply capability of thecompany's range of polyethylene/polypropylene (PE/PP), ultra bulk,airlaid and speciality fibres for binding non-traditional fibrestructures.
This capacity expansion follows the company's recent introductionof global production of new polyester bicomponent fibres. ESFibervisions first added polyester fibres to its portfolio in 2000,with production concentrated at its sites in Japan and China. Theaddition of a polyester bicomponent line in 2006, at its Vardefacility, and in North America in 2005, has resulted in globallystandardized, high-quality polyester bicomponent fibres.
Bicomponent fibres provide a wide variety of performance andproductivity related benefits to nonwovens. By binding together alltypes of fibres (such as glass, hemp, cotton, synthetics, metal,graphite and cellulose) manufacturers can achieve solutions throughnew fibre combinations or meet specific physical propertyrequirements more cheaply.
The company's bicomponent portfolio also contains a broad range ofsheath and core ratios, various polymer combinations, titres (fromvery fine to coarse), all cut lengths including tow, a variety ofcolours, high bulking, splittable, deodorant, compostable andbiodegradable types. They are suitable for a variety of nonwovenapplications including airlaid, wetlaid and carding, for through-air and thermal bonding, needlepunch and spunlacing.
According to the company's President and General Manager, TomZaiser, "Our bicomponent fibres deliver performance andproductivity benefits that can add real value not just within themore traditional hygiene markets, but across the whole nonwovensindustry."