issue 05/2021

10
Years ago
Published in
bioplastics MAGAZINE
Fibre Applications
Spunbond-Film-Composites
Made From
Renewable Resources
Article contributed by
Ralf Taubner
Sächsisches Textilforschungsinstitut e.V.
Department of Spunbondeds/Films
Chemnitz, Germany
www.stfi.de
T
Cross section of composite made of 20gsm PLA-spunbond
nonwoven + 22µm biopolymer film (engraving point)
he main goal of a recent research project was to develop a new
production process for spunbond nonwovens made from PLA to
promote the use of components for spunbond/film composites,
and to seek further technical applications. The investigations carried out
in this research project were particularly directed to further optimising
the process developed in past investigations, and now with the help of
an industrial sized laboratory, the researchers were able to investigate
in particular filament fineness as well as basic weights, and to improve
web uniformity. Finally, complete biologically degradable, extremely
thin and light spunbond/film composites will be developed for hygiene
and packaging applications. This composite will be distinguished by
characteristics similar to conventional textiles regarding haptics and
visual appearance without required increased and more expensive material
usage. Textile PLA polymers were used for spunbond materials
and PLA polymers plasticized by polyethylene glycol (PEG) were used
for film production. All products within the hygiene range should have
basic weights below 30gsm (grams per square meter) - similar to PP
products. A special innovative feature was the combination of spunbond
nonwovens and films made from biopolymers to produce new composite
materials with improved permeability and barrier performance.
First of all, PLA mono and bi-components were examined with regard to
filament fineness and filament strength as well as tensile strength and
elongation, depending on material throughput, cabin pressure, air vol-
ume and filament speed. All filament variants were afterwards submitted
to hot air and/or hot water shrinkage. The dependence of shrinkage
behaviour on filament fineness was clearly proven. Finer filaments with
higher stretching shrank less both in hot air and in hot water compared
to thicker filaments with lower stretching. In case of thermal bonding
all PLA spunbond nonwovens clearly differed depending on temperature
and pressure as well as different basic weights. Some samples were
only pre-bonded by calendering in order to be mechanically bonded
by hydroentanglement or needle-punching in subsequent treatments.
Comparison of the results with hydroentanglement showed that PLA
based spunbond nonwovens can be more easily mechanically bonded
than thermally bonded. Ultimately, PLA bi-component materials were
thermally bonded with different biologically degradable films by means
of calendering. These composites showed different characteristics with
regard to tensile and tearing strengths, steam permeability, haptics and
spunbond/film composite adhesion, depending on the adjusted process
parameters at the calender process and on the manner of film feedin
(inline and off-line procedure). The spunbond material made from
modified PLA showed better haptics and/or softness compared to products
made from standard PLA, however due to the level of polyglycol
worse composite adhesion with films. Finally, composite adhesion could
be significantly improved by Corona pre-treatment of the film and/or
spunbond material. The main characteristics of the newly developed
PLA spunbond/film composites were positively affected by optimization
of process parameters, alternative engraving designs during calendering
and optimized film formulation regarding composite adhesion and
steam permeability.
The author thanks the Federal Ministry for Economics and
Technology, Germany for the promotion of this research project
carried out by the EuroNorm Gesellschaft für Qualitätssicherung and
Innovationsmanagement mbH within the programme „Promotion
of research and development with growth carriers in disadvantaged
regions “ (Innovative Wachstumsträger/INNOWATT).
Properties of developed Spunbond-Film-Composites
made from renewable resources
Tear growth resistance
(acc. Trapeze)
cd
md
cd
md
Water steam
Composite
permeability at 23°C
adhesion Breaking load Breaking load E-Module E-Module
Nonwoven Film
and 100 % humidity
Nonwoven
thickness quality cN/cm N
N
N/mm 2 N/mm 2 g/(m 2 24h)
70:30 --> c/s
20 g/m 2 66020 4,9 8,2 7,1 443 990 194
PLA 6202D:PLA 6751D
70:30 --> c/s
20 g/m 2 61045 2,8 8,4 5,8 215 485 546
PLA 6202D:PLA 6751D
70:30 --> c/s
20 g/m 2 33808 0,8 - 2,5 6,9 - 11,3 5,0 - 6,7 239 - 278 602 - 856 148 - 207
PLA 6202D:PLA 6751D
modified PLA (with 20 g/m 2 66020 0,4 - 2,0 4,9 - 6,5 3,2 - 5,6 127 - 330 497 - 675 477 - 609
Polyglykol)
modified PLA (with 20 g/m 2 61045 0,8 5,7 3,5 160 205 441
Polyglykol)
modified PLA (with 15 g/m 2 66020 1,9 - - - - -
Polyglykol)
PP-nonwoven /PE-Film - - - 19,5 9,9 134 349 51,4
Laminate Fa. Exten
PP-nonwoven /PE-Film - - - 15,3 8 48 282 56
Laminate Fa. Clopay
66020 - 5 8,7 339 569 154
Film without nonwoven
61045 - 6,6 8,7 230 294 541
33808 - 5,2 8,3 236 467 112
18 bioplastics MAGAZINE [05/11] Vol. 6
Cross section of composite made of 20gsm PLA-spunbond
nonwoven + 20µm biopolymer film (engraving point)
In September 2021, Ralf Taubner,
Research associate, Sächsisches
Textilforschungsinstitut said:
PLA – a success story also for the
textile and nonwovens industry 10
years ago, developments and applications
of PLA and other biobased materials
for the nonwoven and textile
sectors were still in their infancy. Up
to now, it has often been a rocky road. All developers
and manufacturers had to contend with high raw
material prices, low availability, and difficulties in
processing. Today, PLA in particular is often at
the top of the agenda for sustainable
new developments in
nonwovens and textiles. For the
polymer, the significant rise
in this industry began about
10 years ago and now many
manufacturers are about to
introduce new products on
its basis, or it has already entered
their portfolio. Hygiene
nonwoven manufacturers, in
particular, have increasingly
focused on this sustainable
feedstock in recent years. In
other application areas such
as agriculture, industrial filters,
home or mobility textiles,
materials made from
biogenic feedstock also
find enthusiastic customers.
The success story of
PLA and other biopolymers
can probably no longer be
stopped and is hopefully
proof that not least a traditional
such as the textile
industry can think and act
forward-looking and contribute
to a sustainable
future economy.
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tinyurl.com/spunbond2011
bioplastics MAGAZINE [05/11] Vol. 6 19
bioplastics MAGAZINE [05/21] Vol. 16 53