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Special Report Special Report

Carbon footprints of Lenzing’s viscose, modal PP/PET Viscose/Modal/Lyocell in Figure 3. The grey columns show
the fossil carbon emissions related to
and lyocell ﬁ bres the production processes for each ﬁ bre
type. The results show a GWP of 4.1
ellulose is a key structural com- of Lenzing’s man-made cellulose and 2.8 t CO eq./t ﬁ bre for PET and
2
ponent of cell walls of plants staple ﬁ bres viscose, modal and PP ﬁ bres respectively. The results for
Cand trees, and therefore a wood- lyocell, produced in Europe and the wood-based process emissions are
based and in a wider sense bio-based Asia. Crude Oil Wood lower than for the PET and PP ﬁ bres
material. Cellulose ﬁ bres are used for  Identify the environmental advan- with 2.5 t CO eq. per t ﬁ bre for “Lenzing
2
a wide range within textile, nonwoven tages and disadvantages of man- Tencel Austria”, 1.2 t CO eq. per t
2
and other industrial applications, rang- made cellulose ﬁ bres compared to ﬁ bre for “Lenzing Viscose Austria” and
ing from home textiles over apparel tex- cotton, bio-based polylactic acid Polymer Production Pulp Production 1.5 t CO eq. per t ﬁ bre for “Lenzing
2
tiles to technical textiles with very high (PLA) ﬁ bres and fossil-based poly- Modal”. This shows that the GWP
property demands like tyre cord. The ethylene terephthalate (PET) and process emissions for the production
Life Cycle Assessment (LCA) study exa- polypropylene (PP) ﬁ bres. For ﬁ bre of wood-based ﬁ bres is lower than the
mined the three types of wood-based comparison, fibres with similar Fibre Production Fibre Production process emissions for the production
cellulose staple ﬁ bres that the company properties to the cellulose ﬁ bres of fossil-based ﬁ bres when both ﬁ bre
Lenzing, a world leading and globally were chosen. types (wood and fossil-based) are pro-
active company with headquarters in duced in Europe.
Austria, can produce – viscose, modal In the goal and scope phase the fol-
and lyocell ﬁ bres. lowing aspects were deﬁ ned: The green columns represent the
Fig. 1: Cellulose staple ﬁ bres  Functional unit: 1 t staple ﬁ bre. biogenic carbon embedded in the
Lenzing produces the three ﬁ bre Lenzing, Photographer: Markus Renner  System boundaries: cradle-to-factory PP/PET Viscose/Modal/Lyocell wood-based products, which can be
types – viscose, modal and lyocell – K. Patel from the Copernicus Institute of gate. Staple Fibres Staple Fibres considered as negative GWP. This
which are sold under the brand names Utrecht University conducted a Life  Impact categories: Global Warming 100% Fossil-based 100% Wood-based is plausible, as during the feedstock
of TENCEL™ (lyocell and modal) and Cycle Assessment (LCA) of man-made Potential 100 (GWP100a), cumula- growth (wood) carbon was removed
LENZING™ ECOVERO™ (viscose) cellulose ﬁ bres viscose, modal and tive energy demand, non-renewable from the atmosphere and embedded in
in textiles, respectively, and VEO- lyocell from Lenzing. In the study the energy use (among others). Fig. 2: Schematic overview of ﬁ bre production for PP/PET and Viscose/Tencel/Modal ﬁ bres wood, then called “embedded biogenic
CEL™ (lyocell, viscose) in nonwovens ﬁ bres were named as follows: Viscose  Impact assessment method: CML pliﬁ ed process scheme of the fossil- carbon”. During the End-of-Life, which
business. The ﬁ bres differ in terms of fibre as “Lenzing Viscose”, modal 2000 baseline method. Lenzing provided the production and woodbased production path- is not considered here, the embedded
their technical as well as haptical and ﬁ bre as “Lenzing Modal” and lyocell data from 2010 for the ﬁ bres viscose, ways is shown in Fig. 2.) biogenic carbon in the wood-based

optical properties due to their different ﬁ bre as “Tencel”. Nowadays, Tencel The system boundaries start at the modal and lyocell (“Tencel”) for the  Data only from European produc- product, but also the embedded fossil
production processes. is the trademark for lyocell and modal extraction of raw materials from the European production site, as well as some tion sites. carbon in the fossil-based product, is

ﬁ bres and the nomenclature used in the environment (cradle). At that time, Lenz- data from an Asian production site. For  Data from the year 2010. released into the atmosphere and both

The viscose ﬁ bre is produced in a study is not anymore in line with cur- ing used wood only from FSC certiﬁ ed the comparison of Lenzing’s cellulose  GWP comparison of the ﬁ bres. contribute to the GWP in a cradle-to-
conventional viscose process. Gene- rent branding. However, here the nam- wood suppliers. Nowadays, Lenzing ﬁ bres with reference ﬁ bres like cotton, grave scenario.
rally, viscose production is energy- ing from the peer-reviewed LCA study operates also other pulp mills and uses PLA, PET and PP ﬁ bres, also for those Nowadays, Lenzing operates three
intensive and requires large quantities is used for the results of the study so PEFC certiﬁ ed wood, too. Additionally, ﬁ bres cradle-to-factory gate data was additional lyocell production sites. The cellulose ﬁ bres contain around
of chemicals such as caustic soda and the reader is able to compare the results Lenzing only uses wood with a quality collected. The fossil-based PET and Therefore, the results shown are not 1.4 to 1.5 t CO eq. embedded biogenic
2
sulphuric acid. The modal ﬁ bre is pro- of this summary with the original LCA which is unable to be used in furniture PP ﬁ bres were modelled using datasets representative anymore, but shall show carbon per t ﬁ bre. If embedded biogenic
duced in a modiﬁ ed viscose process, study. so the wood for the ﬁ bres does not com- from PlasticsEurope representing aver- that already in 2010, companies like carbon is considered as negative GWP
resulting in higher wet modulus ﬁ bres. pete with the need of wood for other age Western European production in Lenzing provided a material with envi- in a cradle-to-gate scenario, it posi-
The lyocell ﬁ bre is produced with the The LCA study was reviewed by high valued products. the year 2000. The production data for ronmental beneﬁ ts. tively inﬂ uences the overall sum (net)
lyocell process, which uses less sol- three external and independent experts. PLA and cotton ﬁ bres were obtained of emissions, which is visualised with
vents and was commercialised in the The reviewers veriﬁ ed that the LCA In the next process step at Lenzing’s from literature sources. Climate change impact results – cradle- the depicted orange dots (see Fig. 3).
early 1990s. Nowadays, all three types was conducted accordingly to the stan- production site in Europe, the wood is to-factory gate boundary Then the net GWP emissions are even
of ﬁ bres are produced simultaneously dards of LCA (ISO 14040/14044). processed to cellulose pulp. Finally, For this summary, the following The cradle-to-factory GWP results lower for the wood-based products, for
in large quantities. the cellulose pulp is transformed into data is selected: in t CO equivalent (eq.) per t staple European data.
2
The goals of the peer-reviewed cellulosic ﬁ bres in Lenzing’s viscose,  Comparative analysis between ﬁ bre for PET, PP, “Lenzing Tencel
LCA of cellulose ﬁ bres LCA study were modal and lyocell processes (factory fossil-based PET/PP and Lenzing’s Austria”, “Lenzing Modal” and “Lenzing CONCLUSION
In 2010, Li Shen and Martin  Identify the environmental impacts gate). man-made cellulose ﬁ bres. (A sim- Viscose Austria” ﬁ bres are visualised The LCA results show that the

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