Nonwovens Technology

Nonwovens Technology

Textile World AsiaSpecial ReportSpunlace Meets SpunbondingThe nonwovens and technical
textiles industries have worked with proven bonding and finishing methods for a long time. Lately,
there has been considerable movement in the spunbond market.Today’s spunbond market is dominated
mainly by calendered spunbonds for the hygiene sector and mechanically needled spunbonds for
geotextiles and roofing applications. In the future, however, new bonding methods such as AquaJet
spunlace technology from Germany-based Fleissner GmbH will be used more and more for the production
of new generations of spunbonds. Fleissner, a leading supplier of spunlace and finishing equipment
for spunbond webs, cooperates with spunbond machinery producers such as Reifenhäuser GmbH & Co.
KG Maschinenfabrik, Germany. Both the spunlace technology and the spunbond process already have
maximum growth rates today. Spunlaced nonwovens — mainly carded staple-fiber webs — already have
replaced and superceded many other nonwoven products that were produced by other bonding methods.
This explains the strong, dominating position spunlace technology has in the market today.

Fleissner finishing lines shown here are used to process bitumen carrier webs made of
polyester spunbond.The market trend of the past few years for the spunbond sector worldwide shows
considerable growth that will increase even more because of new bonding methods such as
spunlacing.The requirements made on spunbond products influence the choice of bonding and finishing
processes used in creating them. It is not important whether polypropylene (PP), polyester, other
homopolymers or bicomponent fibers are used.Based on experience with more than 1,000 continuous
finishing lines for spunbonds, carded webs, wetlaid webs and airlaid webs, Fleissner can design and
deliver finishing lines that meet requirements made on the final products.Proven spunbond products
and technologies include: lightweight webs for the hygiene and agricultural sectors; lightweight to
medium webs used as sarking membranes for the building sector; heavyweight webs for geotextiles;
mediumweight webs for roofing membranes; and mediumweight webs for primary backings on tufted
carpets.New ConceptsOften, lightweight webs that have been calendered do not offer the desired
softness for applications in the hygiene sector. Subsequent treatment on an AquaJet spunlace line
increases the softness and improves the volume. This can be achieved at processing speeds of up to
600 meters per minute (m/min). The spunlace line can be installed both in-line with the spunbond
machine and off-line.The speed and efficiency of the production process for heavy webs for
geotextiles so far have been limited by the relatively low speed of the mechanical needling
process, as higher speeds would destroy the endless filaments, causing a reduction of
strength.Bonding using spunlace technology makes it possible to operate the line at higher
production speeds, which increases line efficiency. At the same time, the tensile strength of the
goods is improved. Thus, fiber costs can be reduced by the reduction in web weights, which
considerably increases the economic efficiency of the process.

Fleissner’s AquaJet spunlace system may be used to make three-layered web structures, such as
this one with cellulose fibers in the middle layer.Production of wet wipes as threelayered
composites by bonding PP spunbond layers on the outside and an airlaid pulp layer on the inside
results in two advantages: drastic improvement of water absorbency because of the cellulose fibers;
and high cost savings because the use of more than 50-percent pulp allows the raw material to be
greatly reduced. Line speeds of 400 m/min to 600 m/min are possible.When producing spunbond
filaments from splittable conjugate fiber cross-sections, AquaJet spunlace technology causes
fibrillation of the fibers so that very fine filaments of less than 0.01 denier may be obtained.
The nonwovens thus produced — for example, Evolon® by Freudenberg Nonwovens Group, Germany — are
used for wipes with special properties because of the large fiber surface. Nonwovens for garments
and coating substrates such as artificial leather also are increasingly being produced.

March/April 2005