Note: Descriptions are shown in the official language in which they were submitted.
1
WO 02/36864 CA 02405885 2002-10-08 PCT/EPOI/12684
Method for the spinning and winding of polyester
filaments using a spinning additive, polyester
filaments obtained by the spinning method, draw
texturing of the polyester filaments and bulked
polyester filaments obtained by draw texturing
The present invention relates to processes for spinning
and winding POY polyester filaments not less than 90~
b y weight, based on the total weight of the polyester
filament, polyb utylene terephthalate (PBT) and/or
polytrimethylene terephthalate (PTMT), preferably PTMT,
b y using spinning additives and also to the POY
polyester filaments ob tainab le b y the process. The
present invention further also relates to processes for
draw texturing the spun and wound polyester filaments
and also tb the b inky polyester filaments ob tainab le
thereby.
The production of continuous polyester filaments and
especially of polyethylene terephthalate (PET)
filaments in a two-step process is already known. In
this process, the first step comprises spinning and
winding flat POY filaments which are fully drawn and
heatset or draw-textured to bulky filaments in a second
step.
An overview of this field is given b y the b ook
Synthetische Fasern b y F. Fourn~ (1995), pub fished b y
Hanser, Munich. However, only the production of PET
fib ers is described and no unified spinning technology
is presented, only an overview describ ing the most
diverse features.
Fib er production from various spinnab le polymers,
including polypropylene, polyamides, polyester, etc.,
forms part of the subject matter of DE-A 38 19 913.
However, only the production of PET fibers is described
s
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in the examples, as is discernible from the temperature
at which the polymer is processed.
The problem with producing continuous polytrimethylene
terephthalate (PTMT) or polyb utylene terephthalate
(PBT) filaments is that POY filaments, not only
directly after spinning and in winding b ut also for
several hours after winding, in the course of storage
at room temperature, exhibit a considerable tendency to
shrink, which leads to yarn shortening. The package is
compressed as a result, so that, in the extreme case,
the package will shrink solid onto the winding mandrel
and can no longer b a removed. Furthermore, the package
will develop a so-called saddle with hard edges and a
waisted center portion. As a result, textile data of
the filaments, for example the Uster value, become less
uniform and prob Iems develop when unwinding the
packages. Such problems do not arise in the processing
of PET fibers.
It is further ob served that, in contradistinction to
PET filaments, POY PBT or PTMT filaments age fast in
the course of storage. Structure hardening occurs and
causes the b oiloff shrinkage to decrease to such a
large extent that aftercrystallization can be detected.
Such PBT or PTMT filaments are only partially suitable
for further processing in that they lead to defects in
draw texturing and to a significant reduction in the
breaking strength of the textured yarn.
These differences between PET on the one hand and PBT
and PTMT on the other are attributable to structural
and property differences, as reported for example in
Chemical Fib ers Int., p. 53, vol. 50 (2000) and
discussed at the 39th International Manmade Fib re
Congress at Dornb irn from September 13 to 15. It is
accordingly b elieved that different chain formations
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are responsible for the property differences.
The first approaches to solving these prob lems are
describ ed in WO 99/27168 and EP 0,731,196 Bl. WO
99/27168 discloses a polyester fib er which is at least
90$ b y weight polytrimethylene terephthalate and has a
b oiloff shrinkage b etween 5~ and 16~ and a b reaking
extension of 20~ to 60~. The polyester fib er described
in WO 99/27168 is produced by spinning and drawing. The
maximum spinning takeoff speed reported is 2 100 m/min.
The process is uneconomical because of the low spinning
speed. In addition, the polyester fib ers obtained are,
as the reported parameters document, highly crystalline
and hence only partially suitab 1e for draw-texturing
processes.
EP 0,731,196 B1 describ es a process for spinning,
drawing and winding a synthetic yarn b y subjecting the
yarn to a heat treatment after drawing and b efore
winding to reduce its tendency to shrink. Synthetic
fib ers which can b a used include polytrimethylene
terephthalate fib ers. In EP 0,731,196 Bl, the heat
treatment is effected b y the synthetic yarn b eing
guided in close vicinity to b ut essentially
contactlessly along an elongate heating surface. The
application of a heat treatment adds to the cost of the
process and, what is more, provides synthetic yarns of
high crystallinity which are only partially suitab 1e
for draw-texturing processes.
The article b y Dr. H.S. Brown and H.H. Chuah:
"Texturing of textile filament yarns b ased on
polytrimethylene terephthalate" Chemical Fib ers
International, Volume 47, Feb r. 1997, p. 72-74
describ es the draw texturing of POY polytrimethylene
terephthalate filaments at texturing speeds of 450
m/min and 850 m/min. According to this disclosure, the
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.
lower texturing speed of 450 m/min is more suitable for
polytrimethylene terephthalate filaments, since fib ers
having better material properties are ob to med in this
case. The b reaking strength of the polytrimethylene
terephthalate fib ers is reported as 26.5 cN/tex
(texturing speed 450 m/min) and 29.15 cN/tex (texturing
speed 850 m/min) and the breaking extension as 38.0$
(texturing speed 450 m/min) and 33.5 (texturing speed
850 m/min).
WO OI/04393 describes PTMT filaments having a b oiloff
shrinkage in the range from 3 to 400. However, this
value is determined immediately after the filaments
have been formed. This value decreases to below 20~ in
the course of 4 weeks of storage under standard .
conditions, as documented by the accompanying figure 1.
Figure 1 describes the change in the b oiloff shrinkage
for three PTMT POY bobbins as a function of the storage
time under standard conditions. The three b ob b ins
investigated had different initial values. Bob bins #16
and 17, having a high initial value of > 405, have a
b oiloff shrinkage after 4 weeks of ab ove 30$ and
preferab 1y of ab ove 40~. However, when the initial
boiloff shrinkage value is less than 40$, it is evident
from bob b in 18 that the b oiloff shrinkage value will
drop to below the critical value of 30~ after a storage
time of 4 weeks.
The b oiloff shrinkage is a measure of the
processibility and the crystallinity of the fibers. The
fib ers describ ed in WO 01/04393 comprise plastics
having a comparatively high crystallinity, which are
significantly more difficult to process and can only be
processed at a lower draw ratio and/or at a lower
texturing speed.
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It is an object of the present invention to provide a
process for spinning and winding POY polyester
filaments not less than 90~ b y weight, based on the
total weight of the filaments, PBT and/or PTMT whereb y
POY polyester filaments are simple to produce and wind
up. More particularly, the POY polyester filaments
shall have breaking extension values in the range of
90~-I65~, a high uniformity with regard to filament
parameters and also a low crystallinity.
It is a further ob ject of the present invention to
provide an economical industrial process for spinning
and winding POY polyester filaments. The process of the
invention shall permit very high spinning takeoff
speeds, preferab 1y ab ove 2 200 rn/min, and high yarn
weights on the package of more than 4 kg.
It is yet a further object of the present invention to
improve the storability of the POY polyester filaments
ob to mable b y the process of the invention. They shall
b a storab 1e for a prolonged period, for example 4
weeks. Ideally, the package shall not compact in the
course of storage, especially shall not shrink solid on
the winding mandrel and form a saddle having hard edges
and waisted center portion, so that there shall b a no
problems unwinding from the package.
According to the invention, the POY polyester filaments
shall b a simple to further process in a drawing or
draw-texturing operation, especially at high texturing
speeds, preferab 1y ab ove 450 m/min. The filaments
ob tainab 1e b y draw texturing shall have excellent
material properties, for example a high b reaking
strength of more than 26 cN/tex and a high b reaking
extension of more than 30~ for HE filaments or more
than 36~ for SET filaments.
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These and other objects not explicitly mentioned b ut
readily derivable or apparent from the related matters
discussed herein at the b eginning are achieved b y a
process for spinning and winding that comprises all the
features of claim 1. Advantageous modifications of the
process according to the invention are protected in
sub claims appendant to claim 1. The POY polyester
filament ob tainab 1e b y the spinning process is
describ ed in an independent product claim. The draw
texturing of the POY polyester filament is claimed in
process claim 7, whereas product claims 8 and 9 relate
to the b ulky filaments ob tainab 1e b y the draw
texturing.
The present invention accordingly provides a process
for producing and winding POY filaments not less than
90~ b y weight, b ased on the total weight of the
polyester filament, polyb utylene terephthalate (PBT)
and/or polytrimethylene terephthalate (PTMT),
preferably PTMT, characterized in that it comprises
a) setting the spinline extension ratio in the range
from 70 to 500,
b) passing the filaments directly upon exit from the
spinneret through a quench delay zone 30 mm to 200
mm in length,
c) quenching the filaments to b elow the
solidification temperature,
d) converging the filaments at a distance between 500
mm and 2 500 mm from the underface of the
spinneret,
e) setting the yarn tension ab ove and b etween the
takeoff godets b etween 0.05 cN/dtex to 0.20
cN/dtex,
f) taking the yarn up at a yarn tension between 0.025
cN/dtex to 0.15 cN/dtex,
g) setting the takeup speed between 2 200 m/min and 6
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.,
000 m/min
h) and using a polyester which contains 0.05 b y
weight to 2.5~ b y weight, b ased on the total
weight of the filament, of additive polymer
extensibility enhancer in admixture.
This unforeseeab 1e process provides POY polyester
filaments which maintain their excellent material
properties even after 4 weeks of storage under standard
conditions. No significant worsening in the uniformity
values of the yarn due to aging and no shrinkage of the
spun fiber on the bobbin are observed.
At the same time, the process of the invention has a
number of further advantages. These include:
The process of the invention is simple and
economical to practice on a large industrial scale.
More particularly, the process permits spinning and
winding at high takeoff speeds of at least 2 200
m/min and the production of packages holding high
yarn weights of more than 4 kg.
~ The use of spinning additives makes it possible to
achieve takeoff speeds of up to 6 000 m/min. The
equipment can b a operated particularly economically
as a result.
~ The POY polyester filaments ob tainab 1e b y the
process can thus b a further processed in a drawing
or draw-texturing operation simply, economically
and on a large industrial scale. In the operation,
the texturing can b a carried out at speeds above
450 m/min.
~ Owing to the high uniformity of the POY polyester
filaments obtainable b y the process, it is simple
CA 02405885 2002-10-08
to achieve good package build to ensure uniform and
sub stantially defect-free dyeing and further
processing of the POY polyester filament.
The filaments obtainable by the draw texturing have
a high breaking strength of more than 26 cN/tex and
a high breaking extension of more than 30~ for HE
filaments and more than 36~ for SET filaments.
The present invention provides a process for producing
and for winding POY polyester filaments not less than
90$ b y weight polyb utylene terephthalate (PBT) and/or
polytrimethylene terephthalate (PTMT), b ased on the
total weight of the filament. Polyb utylene
terephthalate (PBT) and/or polytrimethylene
terephthalate (PTMT) are known to one skilled in the
art. Polyb utylene terephthalate (PBT) is ob to mable b y
polycondensation of terephthalic acid with equimolar
amounts of 1,4-b utanediol and polytrimethylene
terephthalate is ob tainab 1e b y polycondensation of
terephthalic acid with equimolar amounts of
1,3-propanediol. Mixtures of the two polyesters are
also conceivable. According to the invention, PTMT is
preferred.
The polyesters may b a homopolymers or copolymers.
Useful copolymers include especially copolymers which,
as well as PTMT and/or PBT repeat units, contain up to
15 mold, b ased on all the repeat units of the
polyesters, of repeat units of customary comonomers,
for example ethylene glycol, diethylene glycol,
triethylene glycol, 1,4-cyclohexanedimethanol,
polyethylene glycol, isophthalic acid and/or adipic
acid. For the purposes of the present invention,
however, polyester homopolymers are preferred.
The polyesters of the invention may include customary
CA 02405885 2002-10-08
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amounts of further additives as admixtures, such as
catalysts, stabilizers, antistats, antioxidants, flame
retardants, dyes, dye uptake modifiers, light
stab ilizers, organic phosphites, optical b righteners
and delusterants. Preferably, the polyesters include 0
to 5~ by weight of additives, based on the total weight
of the filament.
The polyesters may further include a small fraction,
preferab 1y up to 0.5~s b y weight, b ased on the total
weight of the filament, of b rancher components.
Preferred b rancher components according to the
invention include polyfunctional acids, such as
trimellitic acid, or pyromellitic acid, or tri- to
hexavalent alcohols, such as trimethylolpropane,
pentaerythritol, dipentaerythritol, glycerol or
corresponding hydroxyacids.
In the context of the present invention, the PBT and/or
PTMT are admixed with 0.05 b y weight to 2.5~ b y
weight, based on the total weight of the filament, of
additive polymers as extensib ility enhancers.
Particularly useful additive polymers for the purposes
of the invention include the hereinb elow specified
polymers and/or copolymers:
1. A copolymer containing the following monomer
units:
A = acrylic acid, methacrylic acid or CH2 -
CR-COOR', where R is an H atom or a CH3 group
and R' is a C1_15-alkyl radical or a C5_12
-cycloalkyl radical or a C 6 _ 1 4 -aryl radical,
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B = styrene or C1 _ 3-alkyl-substituted styrenes,
the copolymer consisting of 60 to 98~ by weight of
A and 2 to 40~s by weight of B, preferably of 83 to
98~ b y weight of A and 2 to 17~ b y weight of B,
and more preferably of 90 to 98~ b y weight of A
and 2 to 10$ b y weight of B (sum total = 100$ b y
weight).
2. A copolymer containing the following monomer
units:
C = styrene or C 1 _ 3-alkyl-substituted styrenes,
D = one or more monomers of the formula I, II or
III
l R1
OH ~O
O~
O
cn
rm
where R1, R2 and R3 are each an H atom or a
C1-15-alkyl radical or a C6_14-aryl radical
or a C5_12-cycloalkyl radical,
the copolymer consisting of 15 to 95$ by weight of
C and 2 to 80~ by weight of D, preferably of 50 to
90$ b y weight of C and 10 to 50~ b y weight of D
and more preferably of 70 to 85~ of C and 15 to
30~ by weight of D, the sum total of C and D being
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100 by weight.
3. A copolymer containing the following monomer
units:
E = acrylic acid, methacrylic acid or CH2 =
CR-COOR', where R is an H atom or a CH3 group
and R' is a Cl_15-alkyl radical or a C5-12
-cycloalkyl radical or a C 6 - 1 4 -aryl radical,
F = styrene or C 1 - 3-alkyl-substituted styrenes,
G = one or more monomers of the formula I, II or
III
O
R1 R~
'OH
OH
U
m can
cup
where R1, R2 and R3 are each an H atom or a
C1-15-alkyl radical or a C5-12-cYcloalkyl
radical or a C6_14-aryl radical,
H = one or more ethylenically unsaturated
monomers which are copolymerizab 1e with E
and/or with F and/or G and are selected from
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the group consisting of a-methylstyrene,
vinyl acetate, acrylic esters, methacrylic
esters other than E, vinyl chloride,
vinylidene chloride, halogen-sub stituted
styrenes, vinyl ethers,- isopropenyl ethers
and dimes,
the copolymer consisting of 30 to 99~ by weight of
E, 0 to 50$ by weight of F, >0 to 50~ by weight of
G and 0 to 50~ by weight of H, preferably of 45 to
97°s b y weight of E, 0 to 30~ by weight of F, 3 to
40~ by weight of G and 0 to 30~ by weight of H and
more preferably of 60 to 94$ by weight of E, 0 to
20$ by weight of F, 6 to 30~ by weight of G and 0
to 20°s b y weight of H, the sum total of E, F, G
and H being 100 by weight.
4. A polymer of the following monomer unit:
Rl
~R2
where R1 and R2 are substituents consisting of the
optional atoms C, H, 0, S, P and halogen atoms and
the sum total of the molecular weights of R1 and R
2 is at Least 40. Exemplary monomer units include
acrylic acid, methacrylic acid and CH2 - CR-COOR',
where R is an H atom or a CH3 group and R' is a C
1-15-alkyl radical or a C5_12-cycloalkyl radical
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or a C 6 - 1 4 -aryl radical, and also styrene and C
1 - 3 -alkyl-substituted styrenes.
Details of the production of these sub stances are
described in WO 99/07 927.
Particular preference for the purposes of the present
invention is given to additive polymers and/or
copolymers in the form of bead polymers whose particle
size is in a particularly favorab 1e range. It is
preferable for the additive polymers and/or copolymers
which are to b a used according to the invention, for
example b y mixing into the melt of the fib er polymers,
to b a present in the form of particles having an
average diameter of 0.1 to 1.0 mm. However, larger or
smaller b eads or granules can also b a used. The
additive polymers and/or copolymers can also already be
included in chips of the matrix polymer, obviating any
metered addition.
Preference is further given to additive polymers and/or
copolymers which are amorphous and insolub 1e in the
polyester matrix. They preferab 1y possess a glass
transition temperature of 90 to 200°C, the glass
transition temperature b eing determined in a known
manner, preferab 1y b y differential scanning
calorimetry. Further details are discernible from the
prior art, for example from WO 99/07927, the disclosure
of which is hereb y expressly incorporated herein b y
reference.
Preferab 1y, the additive polymer and/or copolymer is
selected so that the ratio of the melt viscosities of
the additive polymer and/or copolymer and of the matrix
polymer is in the range from 0.8:1 to 10:1 and
preferab 1y in the range from 1.5:1 to 8:1. The melt
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viscosity is measured in a known manner using an
oscillation rheometer at an oscillation frequency of
2.4 Hz and a temperature equal to the melting
temperature of the matrix polymer plus 28°C. For PTMT,
the temperature at which the melt viscosity is measured
is 255°C. Further details may again b a found in WO
99/07927. The melt viscosity of the additive polymer
and/or copolymer is preferably higher than that of the
matrix polymer, and it has b een determined that the
choice of a specific viscosity range for the additive
polymer and/or copolymer and the choice of the
viscosity ratio contrib utes to optimizing the
properties of the yarn product. Given an optimized
viscosity ratio, it is possible to minimize the amount
of additive polymer and/or copolymer added and so,
inter alia, improve the economics of the process. The
polymer b lend to b a spun preferably contains 0.05 to
2.5~ b y weight and more preferab 1y 0.25 to 2.0~ b y
weight of additive polymer and/or copolymer.
The choice of the favorable viscosity ratio provides a
narrow distrib ution of the particle sizes of the
additive polymer and/or copolymer in the polymer matrix
comb fined with the desired fib ril structure for the
additive polymer and/or copolymer in the fib er. The
high glass transition temperature of the additive
polymer and/or copolymer compared with the matrix
polymer ensures rapid consolidation of this fib ril
structure in the spun fiber. The maximum particle sizes
of the additive polymer and/or copolymer amount to
about 1 000 nm immediately following emergence from the
spinneret, while the average particle size is 400 nm or
less. The favorable fib ril structure is obtained after
the fiber has been drawn down, the filaments containing
at least 60~ b y weight of the additive polymer and/or
copolymer in the form of fib rils having lengths in the
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range from 0.5 to 20 pm and diameters in the range from
0.01 to 0.5 um.
Useful polyesters for the invention are preferab 1y
thermoplastically formab 1e and can b a spun into
filaments and wound up. In this context, particularly
advantageous polyesters have a limiting viscosity
number in the range from 0.70 dl/g to 0.95 dl/g.
A polymer melt can b a taken for example directly from
the final reactor of a polycondensation plant or b a
produced from solid polymer chips in a melting
extruder.
One known way of incorporating the spinning additive is
to meter it in molten or solid form into the matrix
polymer and disperse it therein homogeneously to form
fine particles. Advantageously, an apparatus as
described in DE 100 22 889 can be used.
In the process of the invention, the melt or melt
mixture of the polyester is pumped by spinning pumps at
constant speed, the speed being calculated b y a known
formula so that the desired fib er linear density is
ob tamed, into spinneret packs to b a extruded through
the holes in the die plate of the pack to form molten
filaments.
The melt may be prepared for example from polymer chips
in an extruder, in which case it is particularly
favorable for the chips first to b a dried to a water
content 530 pprn and especially to a water content S15
ppm.
The temperature of the melt, which is commonly referred
to as the spinning temperature and which is measured
above the spinning pump, depends on the melting point
of the polymer or polymer blend used. It is preferably
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situated in the range given by formula 1:
Formula 1:
Tm + 15°C 5 Tsp<_ Tm + 45°C
where
Tm is the melting point of the polyester [°C]
Tsp is the spinning temperature [°C].
The specified parameters serve to limit the hydrolytic
and/or thermal viscosity degradation, which should
advantageously b a very low. In the context of the
present invention, a viscosity degradation of less than
0.12 dl/g and especially less than 0.08 dl/g is
desirable.
Melt homogeneity has a direct influence on the
properties of the spun filaments. It is therefore
preferable to use a static mixer having at least one
element and installed b Blow the spinning pump to
homogenize the melt.
Die plate temperature, which depends on the spinning
temperature, is controlled b y the plate's secondary
heating system. Useful secondary heating systems
include for example a spinning b eam heated with
"Diphyl" or additional connective or radiative heaters.
The temperature of the die plates is customarily equal
to the spinning temperature.
A temperature increase at the die plate can be obtained
through the pressure gradient in the spinneret pack.
Known derivations, for example K. Riggert "Fortschritte
in der Herstellung non Polyester-Reifenkordgarn"
Chemiefasern 2Z, page 379 (1971), describ a a
temperature increase of ab out 4°C per 100 b ar of
pressure drop.
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It is further possible to control die pressure through
the use of loose filter media, especially through the
use of steel sand having an average particle size
between 0.10 mm and I.2 mm, preferably between 0.12 mm
and 0.75 mm and/or filter disks, which can b a formed
from woven or nonwoven metal fabrics having a fineness
S40 Nm.
In addition, the pressure drop in the die hole
contributes to the overall pressure. The die pressure
is preferab 1y set b etween 80 b ar and 450 b ar,
especially between 100 bar and 250 bar.
The spinline extension ratio isp, i.e. the ratio of the
takeoff speed to the extrusion speed, is calculated in
accordance with US 5,250,245 via formula 2 from the
density of the polymer or polymer mixture, the
spinneret hole diameter and the filament linear
density:
Formula 2:
igp = 2 . 25~105~ (S~n) ~D2 (cm) /dpf (den)
where
S = density of melt [g/cm3]; for PTMT = 1.12 g/cm3
D = spinneret hole diameter [cm]
dpf = denier per filament [den].
For the purposes of the present invention, the spinline
extension ratio is b etween 70 and 500, preferab 1y
between 100 and 250.
The length/diameter ratio of the spinneret hole is
preferably selected to be between 1.5 and 6, especially
between 1.5 and 4.
The extruded filaments pass through a quench delay
zone. The quench delay zone is configured directly
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b slow the spin pack as a recess zone in which the
filaments emerging from the spinneret holes are
protected from the direct action of the cooling gas and
are delayed in spinline extension or cooling. An active
part of the recess is constructed as an extension of
the spin pack into the spinning b eam, so that the
filaments are surrounded b y heated walls. A passive
part is formed b y insulating layers and unheated
frames. The lengths of the active recess are between 0
to 100 mm and those of the passive part between 20 to
120 mm, subject to an overall length of 30 - 200 mm,
preferably 30 - 120 mm.
As an alternative to the active recess, a reheater can
be disposed below the spinning beam. In contrast to the
active recess, this zone of cylindrical or rectangular
cross section then comprises at least one heating
system independent of the spinning beam.
In the case of radial porous quenching systems which
surround the spinline concentrically, the guench delay
can be attained using cylindrical shrouds,
The filaments are sub sequently cooled to temperatures
below the solidification temperature. For the purposes
of the invention, the solidification temperature is the
temperature at which the melt passes into the solid
state.
In the context of the present invention, it has been
determined to b a particularly advantageous to cool the
filaments down to a temperature at which they are
essentially no longer tacky. It is particularly
advantageous to cool the filaments to temperatures
b slow their crystallization temperature, especially to
temperatures below their glass transition temperature.
Means for quenching or cooling filaments are known from
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the prior art. It is particularly useful according to
the invention to use cooling gases, especially cooled
air. The temperature of the cooling air is preferably
in the range from 12°C to 35°C, and especially in the
range from 16°C to 26°C. The velocity of the cooling
air is advantageously in the range from 0.20 m/sec to
0.55 m/sec.
The filaments may b a cooled using for example single
end systems comprising single cooling tub es having a
perforated wall. Cooling of each individual filament is
ob tained through active cooling air supply or b y
utilizing the self-suction effect of the filaments. As
an alternative to the individual tub es, it is also
possible to use the familiar crossflow quench systems.
In a particular embodiment of the cooling and spinline
extension region, the filaments emerging from the delay
zone are exposed to cooling air in a zone 10 to 175 cm
and preferably 10 - 80 cm in length. A zone 10 - 40 cm
in length is particularly suitable fox filaments having
a linear density at windup <_1.5 dtex per filament and a
zone length of 20 - 80 cm is particularly suitable for
filaments having a linear density between 1.5 and 9.0
dtex per filament. The filaments and the accompanying
air are sub sequently conjointly passed through a
channel having a reduced cross section at a ratio of
the air to the spinline speed at takeoff in the range
from 0.2 to 20:1, preferably in the range from 0.4 to
5:1, b y controlling the cross-sectional constriction
and the dimensioning in the spinline transportation
direction.
After the filaments have b een cooled down to
temperatures below the solidification point, they are
converged to form a yarn bundle. A suitable distance
according to the invention for the point of convergence
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from the underface of the spinneret can b a determined
using conventional methods for online measurement of
the yarn speed and/or yarn temperature, for example
using a laser doppler anemometer from TSI/Germany or an
infrared camera from Goratec/Germany type IRRIS 160. It
is in the range from 500 to 2 500 mm, preferably from
500 to 1 800 mm. Filaments having an as-spun linear
density <_4.5 dtex are preferab 1y converged into a
multifilament bundle at a smaller distance __<1 500 mm,
while thicker filaments are preferably converged at a
greater distance.
It is advantageous for the purposes of the present
invention that preferably all surfaces which come into
contact with the spun filament are fab ricated of
particularly low-friction materials. This sub stantially
avoids b roken filaments and provides higher quality
filament yarns. Particularly suitable fox this purpose
are low-friction surfaces of the "Trib oFil"
specification from Ceramtec/Germany.
The filaments are converged in an oiler pin which
supplies the yarn with the desired amount of spin
finish at a uniform rate. A particularly suitable oiler
pin is characterized b y an inlet part, the yarn duct
with oil inlet orifice and an outlet part. The inlet
part is funnellike, so that contact b y the still dry
filaments is avoided. The contact point of the
filaments occurs within the yarn duct after the supply
of spin finish. Yarn duct and oil inlet orifice are
conformed in width to the yarn linear density and the
numb er of filaments. Orifices and widths in the range
from 1.0 mm to 4.0 mm are particularly suitable. The
outlet part of the oiler pin is configured as a
uniformizing zone, which preferab 1y comprises oil
reservoirs. Such oilers are obtainable for example from
CA 02405885 2002-10-08
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Ceramtec/Germany or Goulston/USA.
The uniformity of oil application is of immense
importance for the invention. The uniformity can b a
determined for example using a Rossa meter as per the
method described in Chemiefasern/Textilindustrie, 42/94
November 1992 at page 896. Preferably, such a procedure
provides standard deviation values for the oil
application which are less than 90 digits and
especially less than 60 digits. Particular preference
for the purposes of the invention is given to oil
application standard deviation values of less than 45
digits and especially less than 30 digits. A standard
deviation value of 90 or 45 digits corresponds
approximately to 6.2~ or 3.1~ of the coefficient of
variation, respectively.
It is particularly advantageous for the purposes of the
present invention to design spin finish lines and pumps
to b a self-degassing to avoid gas b ub b les, since gas
b ub b les can lead to an appreciab 1e variation in oil
application.
According to the invention, it is particularly
preferable for the filaments to be entangled before the
yarn is wound up. In the context of the present
invention, jets having closed yarn ducts will b a found
to be particularly suitable, since such systems prevent
snubbing of the yarn in the feed slot even at low yarn
tension and high air pressure. The entangling jets are
preferab 1y disposed between godets and the yarn exit
tension is controlled via the different speeds of the
inlet and outlet godets. The yarn exit tension should
not exceed 0.20 cN/dtex and should primarily have
values b etween 0.05 cN/dtex and 0.15 cN/dtex. The
entangling air pressure is between 0.5 and 5.5 bar, or
at most 3.0 bar in the case of takeup speeds of up to 3
CA 02405885 2002-10-08
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500 m/min.
The yarns are preferably entangled to node counts of at
least 10 n/m. Maximum nodeless gaps of less than 100 cm
and node count coefficient variation values below 100
are of particular interest. Advantageously, the
employment of air pressures above 1.0 bar provides node
counts >_15 n/m, which are characterized b y high
uniformity in that the coefficient of variation is not
more than 70~ and the maximum nodeless gap is 50 cm. In
actual service, systems of the LD type from
Temco/Germany, the double system from Slack & Parr/USA
or Polyjet from Heb erlein have b een found to b a
particularly useful.
The circumferential speed of the first godet unit is
referred to as takeoff speed. Further godet systems can
b a employed before the yarn is wound uprin the wind
assembly to form packages (bobbins) on formers.
Stab 1e, defect-free packages are a basic prerequisite
for defect-free winding of the yarn and for an ideally
defect-free further processing. Therefore, in the
context of the present invention, the takeup tension
employed is in the range of 0.025 cN/dtex - 0.15
cN/dtex and preferably in the range of 0.03 cN/dtex -
0.08 cN/dtex.
An important parameter of the process according to the
invention is the yarn tension setting above and between
the takeoff godets. As will b a known, this tension is
made up essentially of Hamana's actual orientation
tension, the frictional tension on the yarn guides and
the oiler and the yarn-air frictional tension. For the
purposes of the present invention, the yarn tension
above and between the takeoff godets is in the range
from 0.05 cN/dtex to 0.20 cN/dtex and preferably in the
CA 02405885 2002-10-08
- z2 -
range between 0.08 cN/dtex and 0.15 cN/dtex.
An excessively low tension below 0.05 cN/dtex no longer
provides the desired degree of partial orientation.
When the tension exceeds 0.20 cN/dtex, this tension
will induce a memory effect in the course of winding
and storing the bob bins that leads to a deterioration
in yarn parameters.
The tension is controlled according to the invention by
the distance of the oiler from the jet spinneret, the
frictional surfaces and the length of the gap between
oiler and takeoff godet. This length is advantageously
not more than 6.0 m and preferably less than 2.0 m, the
spinning system and the takeoff machine being disposed
in such a way b y parallel construction as to ensure a
straight yarn path.
The geometric parameters also describe the conditioning
time of the yarn between converging point and takeup.
The fast relaxation during the period has an effect on
the quality of package build. The conditioning time so
defined is preferably chosen to b a between 50 and 200
ms.
The takeup speed of the POY is between 2 200 m/min and
6 000 m/min according to the invention. It is
preferable to choose a speed between 2 500 m/min and 6
000 m/min. It is particularly preferab 1e for the
polymer blends to b a wound up at speeds in the range
from 3 500 m/min to 6 000 m/min.
Advantageously, the process according to the invention
is carried out by adjusting the environment of the yarn
package to b a at a temperature S45°C, especially
between 12 and 35°C, and a relative humidity of 40 -
85~. It is further advantageous to store the POY
CA 02405885 2002-10-08
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packages at 12 to 35°C and a relative humidity of
40-85~ for at least 4 hours prior to further
processing.
After 4 weeks of storage under standard conditions, the
filament according to the invention has
a) a b reaking extension b etween 90~ and 165,
preferably between 90 and 135,
b) a boiloff shrinkage of at least 30~, preferably
>_40~,
c) a normal Uster b elow 1.1$, preferab 1y b elow
0.9~,
d) a birefringence between 0.030 and 0.058,
e) a density of less than 1.35 g/cm3, preferably
less than 1.33 g/cm3,
f) a breaking load coefficient of variation <_4.5$,
preferably 52.5 and
g) a breaking extension coefficient of variation <_
4.5~, preferably 52.5
The term "standard conditions" is known to one skilled
in the art and defined via the DIN 53802 standard.
Under "standard conditions" as per DIN 53802, the
temperature is 2012°C and the relative humidity 65t2~.
It is additionally particularly advantageous for the
purposes of the present invention for the b oiloff
shrinkage to b a b etween 50 and 65% when measured
directly after windup and to b a at least 30$ and
preferably >_40~ after 4 weeks of storage under standard
conditions. It has been determined that, surprisingly,
POY bobbins produced in this way have excellent further
processing properties.
Methods for determining the indicated material
parameters are well known to those skilled in the art.
CA 02405885 2002-10-08
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They are discernib 1e frorn the technical literature.
Although most of the parameters can b a determined in
various ways, the following methods for determining the
filament parameters will prove particularly
advantageous for the purposes of the present invention:
The intrinsic viscosity is measured at 25°C in an
Ub b elohde capillary viscometer and calculated b y the
familiar formula. The solvent used is a 3:2 w/w mixture
of phenol and 1,2-dichlorobenzene. The concentration of
the solution is 0.5 g of polyester per 100 ml of
solution.
The melting point, the crystallization temperature and
the glass transition temperature are each determined
using a DSC calorimeter from Mettler. The sample is
initially heated to 280°C to melt it and then quenched.
The DSC measurement is done in the range from 20°C to
280°C at a heating rate of 10 K/min. The reported
temperatures are determined by the processor.
Filament density is determined in a density gradient
column at a temperature of 23~0.1°C. The reagent used
is n-heptane (C~H16) and tetrachloromethane (CC14). The
result of the density measurement can b a used to
calculate the crystallinity on the basis of the density
of the amorphous polyester Da and the density of the
crystalline polyester Dk. The calculation is described
in the literature and for PTMT for example the
corresponding values are Da = 1.295 g/cm3 and Dk =
1.429 g/cm3.
Linear density is determined in a known manner using a
precision reel and weighing means. The pretension used
is advantageously 0.05 cN/dtex for POY and 0,2 cN/dtex
for DTY.
CA 02405885 2002-10-08
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Breaking strength and breaking extension are determined
on a Statimat apparatus under the following conditions:
the clamped length is 200 mm for POY and 500 mm for
DTY, the rate of extension is 2 000 mm/min for POY and
1 500 mm/min for DTY and the pretension is 0.05 cN/dtex
for POY and 0.2 cN/dtex for DTY. The maximum b reakinq
load values are divided b y the linear density to
determine the breaking strength, and breaking extension
is determined at maximum load.
Boiloff shrinkage is determined b y treating filament
skeins in water at 95~1°C for 10~1 min in a tensionless
state. The skeins are prepared b y reeling at a
pretension of 0.05 cN/dtex for POY and 0.2 cN/dtex for
DTY; the length measurement of the skeins before and
after the thermal treatment is carried out at 0.2
cN/dtex. The difference in length is used to calculate
the boiloff shrinkage in a known manner.
Birefringence is determined b y the method described in
DE 19,519,898, the disclosure of which is explicitly
incorporated herein by reference.
The crimp parameters of the textured filaments are
measured in accordance with DIN 53840 Part 1 using a
Texturmat apparatus from Stein/Germany at a development
temperature of 120°C.
The normal Uster values are determined using a 4-CX
Uster tester and are reported as Uster ~ values. The
testing speed is 100 m/min and the testing time 2.5
min.
The POY according to the invention is simple to further
process, especially draw texture. In the present
invention, draw texturing is preferably carried out at
a texturing speed of at least 500 m/min and
particularly preferab 1y at a texturing speed of at
CA 02405885 2002-10-08
- 26 -
~, '
least 700 m/min. The draw ratio is preferably at least
1.35:1 and especially at least 1.40:1. It will b a
particularly advantageous to draw texture on a high
temperature heater type machine, for example an AFK
machine from Barmag.
The bulky filaments produced in this way exhibit a low
numb er of defects and on dyeing at the b oil with a
disperse dye without carrier an excellent depth of
shade and uniformity of color.
Bulky SET filaments produced according to the invention
preferab 1y have a b reaking strength of more than 26
cN/tex and a breaking extension of more than 36~. In
the case of bulky HE filaments, which are obtainable
without thermal treatment in a second heater, the
breaking strength is preferably more than 26 cN/tex and
the breaking extension more than 30~.
The b ulk and elasticity b ehavior of the filaments
according to the invention is excellent.
Illustrative embodiments of the invention will now b a
more particularly described without the invention being
limited to these examples.
Examples 1 to 3
CA 02405885 2002-10-08
27 _
Spinning and windincr
PTMT chips having an intrinsic viscosity of 0.93 dl/g,
a melt viscosity of 325 Pa s (measured at 2.4 Hz and
255°C), a melting point of 227°C, a crystallization
temperature of 72°C and a glass transition temperature
of 45°C were tumble dried at 130°C to a water content
of 11 ppm.
The chips were melted in a 3E4 extruder from Barmag, so
that the temperature of the melt was 255°C. This melt
had added to it various amounts of Plexiglas 7N
polymethyl methacrylate from Rohm Gmb H/Germany as an
extensibility enhancer which had beforehand been dried
to a residual moisture content of less than 0.1~.
For this purpose, the additive polymer was melted in a
melting extruder, fed using a gear wheel metering pump
to the feed means and fed from there through an
injection nozzle in the flow direction into the
polyester component. The two melts were homogenized and
finely dispersed in an SMX static mixer from Sulzer
having 15 elements and an internal diameter of 15 mm.
The melt viscosity of the Plexiglas 7N was 810 Pa s
(2.4 Hz, 255°C), as a result of which the ratio of
additive and polyester melt viscosities was 2.5:1.
The transported amount of melt was 63 g/min coupled
with a residence time of 6 min, and the amount metered
from the spinning pump to the spinneret pack was
adjusted so that the POY linear density was ab out 102
dtex. Various takeup speed settings were used. One
element of an HD-CSE type static mixer from Fluitec
having an internal diameter of 10 mm had been installed
below the spinning pump, but above the point of entry
into the spinneret pack. The secondary heating systems
for the product line and the spin b lock, which
CA 02405885 2002-10-08
- 28 -
contained the pump and the spinneret pack, had been set
to 255°C. The spinneret pack contained 350-500 um steel
sand 30 mm in height and also a 20 um nonwoven filter
and a 40 um woven filter as filter media. The melt was
extruded through an 80 mm diameter spinneret plate
containing 34 holes 0.25 mm in diameter and 1.0 mm in
length. The die pressure was about 120-140 bar.
The quench delay zone was 100 mm in length, made up of
30 mm in heated walling and 70 mm in insulation and
unheated frame. The molten filaments were quenched with
air flowing horizontally against the spinline over a
length of 1500 mm. The quenching air had a flow rate of
0.35 m/sec, a temperature of 18°C and a relative
humidity of 80~s. The filaments became solid at ab out
800 mm below the spinneret.
A yarn oiler positioned at a distance of 1 050 mm from
the spinneret was used to apply spin finish to the ends
before converging. The oiler had a TriboFil surface and
an inlet opening 1 mm in diameter. The amount of spin
finish applied was 0.40, based on fiber weight.
The converged spinline was then fed to the winding
machine. The distance between the oiler and the first
takeoff godet was 3.2 m. The conditioning time was
between 105 and 140 ms. A pair of godets was S-wrapped
b y the yarn. Situated between the godets was a Temco
entangling jet, which was operated using an air
pressure of 1.5 bar. In line with the speed setting,
the takeup speed of the Barmag SW6 winder was set in
such a way that the takeup yarn tension was 5 cN. The
room conditions were adjusted to 24°C and 60$ relative
humidity so that a temperature of ab out 34°C ensued in
the environment of the yarn package.
A significant increase in productivity was obtained for
CA 02405885 2002-10-08
- 29 -
,~
all amounts of additive added. The 10 kg b ob b ins
produced were readily removab )e from the winding
mandrel. The POY yarns obtained were notable for good
time constancy of the yarn properties over a storage
period of 4 weeks under standard conditions as defined
in DTN 53802. The b oiloff shrinkage directly after
spinning and'winding was found to b a in the range of
51-54g. The texturability and the uniformity of dyeing
achieved were found to b a excellent. The draw ratio to
be used was surprisingly high for the POY speeds used.
The other parameters and characteristic data are
summarized in tables 1 to 4.
Table 1: Experimental parameters
Exp~rimental parameters Example Example Example
1 2 3
Additive [~] 0.5 0.7 1.0
concentration
Takeoff speed (m/min] 3011 3520 4022
Takeup speed [m/min] 3005 3500 4000
Spinline extension 183 182 181
ratio
Yarn tensions
above godetsl [cN] I3 15.5 16
between godetsl max [cN] 12 13 12.5
above godets2 [cN/dtex] 0.13 0.15 0.16
between godets2 max [cN/dtex] 0.11 0.13 0.12
-
Yarn tension) (cN] 6.3 5.9 6.4
Yarn tension2 [cN/dtex] 0.062 0.058 0.062
Z: absolute
2: based on linear density
Table 2: Material properties of PTMT POY filaments)
Material properties Exempla Example Example
~ 1 2 3
_
~
Linear density jdtexj 102 102.5 103
Breaking strength (cN/dtex] 20.2 21.8 22.3
Breaking extension [~] 132.7 115.4 98.2
Normal Uster [~] 0.80 0.90 0.94
Boiloff shrinkage [~] 48 44 38
CA 02405885 2002-10-08
- 30 -
Birefringence103 0n 36 47 51
Density [g~cm3~ 1.315 1.318 1.320
Breaking load CV [$] 1.7 1.5 2.1
Breaking extension CV [~] 1.9 1.9 3.3
CV: coefficient of variation
1: measured after 4 weeks of storage under normal
conditions
CA 02405885 2002-10-08
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Draw texturing
The PTMT filament bobbins were stored for 4 weeks under
standard conditions as defined in DIN 53802 and then
presented to a Barmag FK6-S-900 draw texturing machine.
The experimental parameters for draw texturing to
produce SET filaments are summarized in table 3 and the
material properties of the resulting b ulky SET
filaments in table 4.
Texturing defects were determined using Barmag's
UNITENS system at the following limiting value
settings: UP/LP = 3.0 cN, UM/LM = 6.0 cN.
Table 3: Experimental parameters of draw texturing
Experimental parameters Example Example Exampl~
1 2 3
Speed [m/min] [m/min] 700 700 700
Draw ratio 1:1.70 1:1.60 1:1.44
D/Y ratio 2.1 2.1 2.1
Heater 1 temp. [C] 155 155 155
Heater 2 temp. [C] 160 160 160
Texturin defects [n/10 km] 0 0 0
Yarn tension
F1, above assembly (cN] 17 18 19
F2, below assembly (cN] 19 21 21
F2-CV ($] 078 0.93 0.89
F2-CV: coefficient of variation of F2
CA 02405885 2002-10-08
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Table 4: Material properties of draw-textured filaments
Material properties Example Example Example
1 2 3
Linear density [dtex] 67 69 79
Breaking strength [cN/tex] 26.9 29.6 28.2
Breaking extension [~J 38.6 37.8 38.0
Inspection of uniform uniform uniform
dyeability
Crimp rigidity [$] 84 85 79
Crimp contraction [$] 25 24 23
CA 02405885 2002-10-08
