LENZING
PROFILEN@
YARNSAND
FIBRES
Adalbert Wimmer, Lenzing AG
Lenzing PROFILEN@ is the registered trademark of high
tenacity PTFE yarns and new crimped PTFE fibres from
Lenzing for the manofacture
of needlefelts.
Lenzing PROFILEN@ yarns are used amongst other things
(e.g. dental floss) in high temperature
filtration as scrims
and sewing thread.
Lenzing PROFILENa ist das eingetragene
Warenzeichen
für PTFE-Garne mit hoher Festigkeit und neu gekräuselte
PTFE-Fasern
aus Lenzing
für die Herstellung
von
Nadelfilzen.
Lenzing PROFILEN@-Garne werden neben
anderen Anwendungen (z.B. Zahnseide) in der Hochtemperaturfiltration
als Gitterstoffe und Nähgarn verwendet.
Our Programme
the manufacture
supply this yarn
each in cartons
These yarns are wound on king cones with a height of
155 mm and a base diameter of 85 mm. Six cones of this kind
are packed in one Canon; one carton weighs approx. 3 kg.
includes the weaving yarn type 204/3008 for
of scrims for the fabrication of needlefelts. We
on conical Cross wound-cones of approx. 1 kg
of 24 cones each.
Typrcal data:
titre:
440 dtex
twist:
300 T/m S
tenacity:
25 cN/tex min.
(typical stress-elongation diagram in fig.1)
elongation:
approx. 5 %
shrinkage:
3 % at 200 “C
N
P
Tenacity of Yarn
at rising temperature
i
1
0
0
50
100
150
Temperature
200
“C
250
l30( 3
FIT 2
Since these yarns are used almost exclusively in high temperature filtration, tenacity and elongation values at higher temperatures are of particular significance as opposed to tenacity at
ambient temperature.
As with every thermoplastic, the tenacity drops the higher the
temperature becomes.
One surprising fact with regard to PTFE is, however, that the
falling curve levels out at a temperature of approx. 200°C and
ceases to fall further as from 250°C. The value to which the tenacity falls is thereby largely independent of the starting tenacity at room temperature (35, 30 or 25 cN/tex). At 2OO”C,
the tenacity equals approx. 7 cN/tex (fig. 2). If the temperature
rises further, the tenacity remains almost constant. We
IO
5
% Elongation
L
Elongation
of Yarn
at rising temperature
15
25)
Flg 1
Apart from weaving yarns, we also manufacture sewing thread
for the fabrication of filter bags. Both types of yarns tan also be
manufactured in different colours upon customers’ request
(spun dyed). The sewing thread is a treble twisted yarn with the
following typical data:
titre:
twist:
breaking forte:
elongation:
shrinkage:
1350 dtex
400 T/m Z 3-ply
30 N min.
approx. 5%
3 % at 200°C
8
‘E
9
0
iil’
s0
I
I
1
l
I
2
100
150
Temperature
200
“C
250
300
Fig. 3
- Lenzinger
conducted our measurements up to a temperature of 325°C
and even at this temperature, which we all know is only 2°C
below the crystallite melting Point, this level remains intact.
Surprisingly, the elongation of the yarns also behaves very
favourably: elongation increases, commencing at about 6 % up
to approx. 12 %, and then it falls again to approx. 5 %
(fig. 3). This means that our compact sintered Lenzing
PROFILEN’ has only a very slight tendency to flow and this is
very unusual for thermoplastics.
We attribute the stress-elongation properties of our Lenzing
PROFILEN’ yarns, which are very favourable for use in high temperature filtration, to the special process we use to manufacture these yarns. The reason would seem to reslde in the complete
sintering of our PTFE yarns they have no rricroporous structure.
Microporous products require different conditions for their manufacture and they differ slightly in their behaviour compared to our
compact yarns. At 200 “C, the tenacity value is approx. the
same as for Lenzing PROFILEN”’ yarns. If the temperature is raised further however, tenacity of the microporous yarns drops
slightly more than is the case with Lenzing PROFILEN ’yarns (fig.
2). With respect to elongation, the differente is greater. Even if
the material displays, in principle, similar ch,aracteristics in the
curve, the maximum value for elongation for imicroporous yarns
at over 20 %, is clearly above the 12 % for Lenzing PROFILEN”
yarns (fig. 3).
And finally we were also able to demonstrate the properties of
the Lenzing PROFILEN yarns described above in the felt. The
curve of the tenacity is demonstrated in figure 4. The scrim hereby has a weight of 130 g/m-. The theoretica tenaclty at room
temperature, on the basis of yarn tenacity would, therefore,
equal approx. 830 N/5cm
bd
P
Berichte 75196
As a result of these cellulose residues and the raw surface of the
fibres, needlefelts tan be processed. However, in the application itself, these properties which are positive for processing
prove to be a disadavantage - cleaning is hindered by the cellulose residues since they hold back the dust. This tan, in the
final Stage, lead to the clogging up of the felts making it necessary to replace them. Moreover, it has proved necessary to
keep the felt weights relatively high in Order to achieve the
collection rates demanded with respect to PTFE.
Several years ago Lenzing AG attempted to use the pure
PTFE fibres they had manufactured using their “Split peel process” to fabricate needlefelts. Unfortunately, they were unsuccessful. The “anti-adhesion” properties, which are an
advantage in filtration, and the relatively high titre of 10 dtex
made it extremly difficult to produce a felt at an industrial
level.
New revolutionary PTFE fibres:
Following long and difficult development work, Lenzing AG has
succeeded using a new kind of process, in manufactunng pure,
and crimped PTFE-fibres without any kind of impurity. This is a
peculiarity for PTFE and was thought to be impossible. However,
the fibre is not only crimped but also has a finer titre than
previous PTFE fibres - measurements revealed an average
fineness of 2.4 den.
Since the titre data do not take the specific weight of the
fibres into consideration we would like to briefly take a comparison with acrylrc fibres. Acrylic fibres have a specific weight of
1.14 g/cm, PTFE has a specific weight of 2.17 g/cm From this
we deduce that a PTFE fibre of 2.4 den is comparable in crosssection with a polyacrylic fibre of 1.26 den. One tan, therefore,
describe this as a fine fibre.
The titre spread generally represents a curve as tan be seen in
figure 5. lt displays a spread of 0.69 - 5.4 den at a mean value
of approx. 1.7 den.
LENZIN(
Tenacity of Scrim
Fabric
at rising temperature
r
Spread of Titre
bd Lenzing Profilen Fibre
P
LENZING
600
12
0
50
100
150
Temperature
200
“C
250
C
8
4
z
2
0,69
Lenzing
1,50
2,32
3,14
3,95
Titre in den
4.77
5,5<
PROFILEN@’ Fibres:
State of the art of technology:
A reputable PTFE polymer manufacturer developed the “matrix
spinning process” in the 1950’s which permits the manufactu
re of fibres with the help of cellulose as a matrix. These fibres
are dark-brown as a result of the 3 - 5 % residual cellulose.
With this Lenzing PROFILEN” fibre, felt manufacturers now
have a PTFE fibre which emphasises all the positive
propetiies of PTFE, tan be processed to felts wrth excellent
results and, as a result of the finer and blended titre, also
produces better frltration propetiies
.
Fibre
From the initial processing trials to make feil we would now
like to provide you with some processing recommendations:
3 Main cylinder and carding equipment with metallic
clothings.
3 Application of an antistatic agent to the flbre before processing: 1% Catolin A 32 made from a 70% solution
applied a6 a 20% solution; time of effect 24 hours. Albon
Chemie supplies the Catoiin A 32, Carl Zeiss Str. 41,
0-72555 Metzingen: Tel: 07123 1231, Fax07123 61690.
0 Needles: 15 x 16 x 36 x 3 RB 26, A 06/08 PP (Messrs.
Singer)
0 Needling: 4 x 16 mm and 2 x 13 mm with 100stitchesinn2
for each passage.
In thisway, a600g/m2feltwasmanufacturedonascrimof130
g/m* and the filtration behaviour was examined. The
following data was obtained:
0 thickness: 1.5 mm at 2.0 cN/cm2
0 apparent density: 0.40 g/cm3at 2.0 cWcm2
0 air permeability:
65 Vdm2min at 200 Pa
160 Vdm2min at 500 Pa
0 separation rate:
0.999 and larger rising after 45 min rising to 1.O after60 min
with a crude gas concentration of 5 g/m3 and the use of the
following test dust:
flue gas ash made of a medium load coal-fired power station with flue gas desulphurisatlon, spray absorption, extremely pourable, 2.5 - 3.0 pm average particle size. This is a
partialarty criticaltype of dust and produces an unstationaiy
fiitration condition particularly in the starting up stage of a
plant and following purification.
0 Flue gas speed: 5 mm/s
We are now in a position to state that, as a result of shrinkage,
this pure PTFE fibre can be processed vvlthout any difficulty to
a fleece and, therefore, to a needlefelt. From the initial tests
which have been conducted so farit can even be concluded
that machine performances can be increased compared to
other PTFE fibres. More-over, lighter felts c
m be produced
which offer the same filter efficiency as the heavler conventional PTFE-felts. In addrtion. It should also be possible to extend
the filter wvce life as a resuit of releasa characteristics
Conclusion:
0 Scrims made of Lenzing PROFILENO guarantee good
dimensional stability of the filter bags as a result of tha
low elongation.
0 Lenzing PROFILENO sewing t h m d guarantees high
seam durability.
0 Lenzing PROFILEN. fibres hsve a tine titre, they are
made of pum PTFE, they have a high crimp level, they
pmduce a good filter efkiency, they are easy to pro-
cess.