Title of Invention

"A 100-400 DTEX TYRE CORD FABRIC WEFT YARN"

Abstract A 100-400 dtex tyre cord fabric weft yarn comprising a heat-protected nylon-6,6 multifilament, characterized in that the base yarn combines the following features: 80% extension SLASE of 6 cN/tex to 12 cN/tex ultimate tensile stress elongation of 150 to 300% tenacity > 14 cN/tex reversibility limit of 5 cN/tex to 10 cN/tex 160°C thermal shrinkage force of 0.15 cN/tex to 0.8 cN/tex 160°C free shrinkage
Full Text Weft yarn and piuJuiLioa ol a weft yai-n from hsaHr
protected nylon 66 fur—byre cord fabric
The present invention relates to a 100-400 dtex
tyre cord fabric weft yarn comprising a heat-protected
nylon-6,6 multifilament and to a process for producing a
weft yarn.
Weft yarn for tyre cord fabric and a process for
making it from polyester POY are known (WO-A-96/2391) .
The yarns produced from polyester POY filaments have very
low thermal stability. Lower spinning speeds do not yield
any improvement. The filament yarn turns brittle on the
relaxation heater at 220°C, losing a large proportion of
its strength and residual elongation at break.
It is an object of the present invention to
provide a PA 66 tyre cord fabric weft yarn having high
thermal stability, a defined reversibility limit,
adequate tenacity and slip resistance and also a high
ultimate tensile stress elongation.
It is a further object to provide a process for
producing tyre cord weft yarns which, following impregnation,
exhibit an ultimate tensile stress elongation
which ensures spreading of the cord threads in tyre
manufacture without weft thread breakages.
This object is achieved according to the invention
when the base yarn combines the following features:
80% extension SLASE of 6 cN/tex to 12 cN/tex
ultimate tensile stress elongation of 150 to 300%
tenacity > 14 cN/tex
reversibility limit of 5 cN/tex to 10 cN/tex
160°C thermal shrinkage force of 0.15 cN/tex to
0.8 cN/tex
160°C free shrinkage > 1%.
Such a yarn has the advantage of facilitating
homogeneous warp thread distribution in tyre construction
due to pronounced flow characteristics in the fabric. In
addition, this yarn constitutes a single-component weft
yarn which does not give rise to unpleasant and harmful
dust in weaving, as is customary with the use of natural
fibres. It is additionally intended to withstand high
thermal stress during the impregnating step, to exhibit
hardly any widthwise contraction and, in the construction
of a tyre, to facilitate very homogeneous cord warp
thread spreading and so be universally useful for tyre
cord fabrics based on nylon, polyester and aramid.
At an extension of 80%, preferably 90-150%, a
load of 6 cN/tex to 12 cN/tex, preferably 6-10 cN/tex, is
advantageous. Loads higher than 12 cN/tex at the stated
extension have the disadvantage of inhomogeneous warp
thread distribution when the radial tyre expands on the
tyre construction machine. Loads below 6 cN/tex at the
stated extension lead, not only under uniform but also
under local loads, for example in the course of storage
of fabric bales, to irreversible weft thread stretching
and so to inadequate stability with regard to warp thread
parallelity. This gives rise to poor or unusable tyre
carcasses.
An ultimate tensile stress elongation of preferably 180-280%, is advantageous. Ultimate tensile
stress elongations of more than 300% lead to excessively
high stretching under customary loads in the production
of tyre cord fabrics; an ultimate tensile stress
elongation of less than 150%, by contrast, leads to
insufficient extensibility reserve, resulting in insufficient
weft deformation or even weft yarn breakages in
the fabric. In both cases, the resulting tyre carcasses
are inhomogeneous and so the tyres which are manufactured
therefrom are as well.
It is advantageous for the weft yarn to have a
tenacity of at least 14 cN/tex in order that the peak
stresses obtaining during the various processing steps
cannot lead to weft yarn breakages.
A reversibility limit of 5 to 10 cN/tex is
particularly advantageous. A reversibility limit of less
than 5 cN/tex means that there is no way of ensuring
dimensional stability on weft insertion or fabric width
stability until processing into the tyre. If the reversibility
limit is greater than 10 cN/tex, the force which
results during the vulcanization step is not sufficient
to spread the individual cord threads uniformly.
A thermal shrinkage force of 0.15 to 0.8 cN/tex
has the advantage of virtually no widthwise contraction
occurring during the impregnating step and hence of
ensuring a homogeneous cord warp thread distribution,
especially in the case of fabrics having weft yarn laidin
selvages, during this step as well; a thermal
shrinkage force of greater than 0.8 cN/tex will, despite
the forces applied by spreading rolls to the weft threads
during the impregnating step, result in thread
shortening, which jeopardizes the required homogeneity.
This leads, especially at the fabric selvages, to undesirable
warp thread compaction. In the case of thermal
shrinkage forces of less than 0.15 cN/tex, the thermal
stress on the carcass fabric during impregnation is
sufficient to give rise to thread lengthening, which
jeopardizes the parallelity of the warp threads.
According to the invention, it is not absolutely
necessary for all the base yarn features to be within the
claimed limits at one and the same time.
It is advantageous for the weft yarn to combine
the following features following a tensionless hot air
treatment at 235°C for 5 min:
ultimate tensile stress elongation of greater than
80%
80% extension SLASE of 6 cN/tex to 14 cN/tex
reversibility limit of 5 to 10 cN/tex
no uncontrollable change in length due to the heat
treatment.
Ultimate tensile stress elongations of greater
than 80%, preferably greater than 110%, are advantageous.
Ultimate tensile stress elongations of more than 110% for
the impregnated fabric weft yarn have been found to be
particularly useful, since this prevents any random
breakage of individual weft threads, especially during
the expanding of the tyre blanks on the tyre construction
drum, during the process-based spreading of the carcass.
Isolated weft thread breakages lead to nonuniform cord
thread spacing in the carcass and so to inadequate tyre
roundness.
The impregnated weft yarn has an 80% SLASE of
less than 14 cN/tex, preferably less than 12 cN/tex. An
80% SLASE of more than 12 cN/tex increases, in the construction
of a tyre, the risk of unlevel distribution of
the warp threads as the carcass is expanded to the final
tyre circumference. The impregnated yarn is conventionally
RFL-dipped and then heat-set at temperatures of up
to 245°C, preferably at 210-235°C for 45-200 s.
The reversibility limit is less than 10 cN/tex,
preferably less than 8 cN/tex, after the hot air treatment.
This has the advantage that spreading forces that
occur during vulcanization are sufficient to deform the
warp threads so as to ensure uniform distribution of the
carcass threads.
The starting material used for the feed yarn of
the process of the present invention is a nylon-6,6 LOY.
Instead of pure nylon-6,6 it is also possible to use a
copolyamide at at least 85% by weight. Examples of
suitable copolyamides are PA 6, PA 6,10 and aramid. The
nylon-6,6 LOY has generally been drawn at spinning takeoff
speeds of less than 1800 m/min. The starting yarn is
heat-protected with a copper additive at at least 30 ppm
of Cu, preferably at 60-80 ppm of Cu.
In a particularly suitable one-stage production
process starting from an LOY, nylon-6,6 LOY filaments
heat-protected with at least 30 ppm of Cu are drawn
between 10 and 200%, preferably between 40 and 150%,
especially between 40 and 125, and then entangled by
means of a compressed gas to at least 10 nodes/m, preferably
at least 15 nodes/m. The process has the advantage
of producing a compact filament assembly having a
relatively rough and slip-resistant surface. The drawing
of the LOY yarn can be effected cold or hot, with or
without snugging pin.
In a varied process, the nylon LOY filaments are
drawn between 10 and 200% in a first process step and
then entangled, simultaneously or subsequently, to at
least 10 nodes/m by means of a compressed gas and relaxed
by between 0 and 30% at 150 to 235°C, preferably 200 to
225°C, in a second process step. This has the advantage
of producing lower shrinkage values and lower LASEs.
In a further variant of the process, the weft
yarn is additionally set, or afterdrawn, at a temperature
between 150 and 235°C, especially between 180 and 225°C,
by 0 to 10%. This has the advantage of providing for a
further reduction in the shrinkage values and thus of
making it possible to conform shrinkage properties to
particular tyre construction process conditions.
The weft yarn is used as a base yarn and is
particularly useful for tyre cord fabrics.
Methods of measurement:
Generally carried out after 24 h conditioning of
the bobbins under standard conditions of 20 ± 2°C and
65 ± 2% relative humidity.
Linear density:
Determination of the fineness of yarns and
threads by the reel method (DIN 53 830 Part 1).
Tensile test:
Simple tensile test on yarns and threads in the
conditioned state (DIN 53 834 Part 1)
- clamped length 100 mm
- rate of extension 1000 mm/min.
Modulus:
Slope of the quasi linear part of the lower
stress-strain curve.
Reversibility limit:
Equivalent to the elasticity limit =» stress at
which there is a transition from reversible to irreversible
extension.
SLASE:
Specific load in cN/tex at stated extensions (2%,
5%, 10% and 80%).
Free thermal shrinkage: (residual or permanent)
Permanent change of length in % after a 15 min
tensionless hot air treatment at 160°C and a subsequent
15 min cooling down and conditioning in a standard
atmosphere.
Effective shrinkage:
Change of length in % after 15 min treatment at
160°C and 0.1 cN/tex pretensile force.
Effective shrinkage force:
Change of force in cN/tex of a sample firmly held
at both ends with 0.1 cN/tex due to the 15 min hot air
treatment at 160°C. The measurement is in each case
carried out during the application of heat.
Embodiments of the invention will now be more
particularly described by way of example.
Examples 1:
A nylon-6,6 having a Cu content of 60 ppm was
conventionally spun into a 519 dtex, 34 filament LOY
having the properties recited in the following table.
This starting material was then cold-drawn by 125% with
a snugging pin at a take-off speed of 450 m/min (take-off
godet in the drawing zone) and wound up with a linear
density of 224 dtex. The detailed yarn properties can be
seen in said aforementioned Table 1.
Example 2:
A nylon-6,6 having a Cu content of 30 ppm was
conventionally spun into a 550 dtex, 17 filament LOY
having the properties recited in the following table.
This starting material was then drawn by 100% at 160°C
without a snugging pin at a take-off speed of 60 m/min
(take-off godet in the drawing zone) and wound up with a
linear density of 290 dtex. The detailed yarn properties
can be seen in said aforementioned Table 1.
Example 3:
A nylon-6,6 having a Cu content of 60 ppm was
conventionally spun into a 252 dtex, 34 filament LOY
having the properties recited in the following table.
This starting material was then cold-drawn by 40% with a
snugging pin at a take-off speed of 120 m/min (take-off
godet in the drawing zone) and wound up with a linear
density of 190 dtex. The detailed yarn properties can be
seen in said aforementioned Table 1.
Example 4:
A nylon-6,6 having a Cu content of 60 ppm was
conventionally spun (similarly to Example 3) into a
252 dtex, 34 filament LOY having the properties recited
in the following table. This starting material was colddrawn
by 50% with a snugging pin at a take-off speed of
143 m/min (take-off godet in the drawing zone). In a
further continuous process step, a 25% relaxation was
carried.out at 220°C by means of a contact heater 25 cm
in length. The yarn linear density following these
treatments was 215 dtex. The detailed yarn properties can
be seen in the aforementioned Table 2.
Example 5:
A nylon-6,6 having a Cu content of 60 ppm was
conventionally spun into a 273 dtex, 34 filament LOY
having the properties recited in the following table.
This starting material was then cold-drawn by 11% without
a snugging pin at a take-off speed of 390 m/min (take-off
godet in the drawing zone) and wound up with a linear
density of 243 dtex. The detailed yarn properties can be
seen in said aforementioned Table 2.
Example 6:
A nylon-6,6 having a Cu content of 60 ppm was
conventionally spun (similarly to Example 3) into a
252 dtex, 34 filament LOY having the properties recited
in the following table. This starting material was then,
in a first step, cold-drawn by 50% with a snugging pin at
a. take-off speed of 135 m/min (take-off godet in the
drawing zone). In second continuous process step, a 25%
relaxation was carried out at 220°C by means of a convection
heater 65 cm in length. In the third continuous
process step, the material was post-set at 210°C on a
contact heater 25 cm in length without further drawing.
The yarn linear density resulting from these treatments
was 214 dtex. The detailed yarn properties can be seen in
the aforementioned Table 2.
Example 7 (relaxation series):
A nylon-6,6 having a Cu content of 60 ppm was
conventionally spun (similarly to Example 1) into a 519
dtex, 34 filament LOY having the properties recited in
the following table. This starting material (LOY) was
then, in a first step, cold-drawn by 105% with a snugging
pin at a take-off speed of 80 m/min (take-off godet in
the drawing zone). In a second continuous process step,
a convection heater 65 cm in length was used at 225°C to
produce three variants with 5%, 15% and 25% relaxation.
The yarn linear densities resulting from these treatments
were between 283-349 dtex. The detailed yarn properties
can be seen in the aforementioned Table 3.
Example 8 (addition to Example 7):
The 25% relaxation variant described in Example
6 was additionally post-set in a third process step at
210°C in a contact heater 25 cm in length without further
drawing. The yarn linear density resulting from this
treatment was 343 dtex. The detailed yarn properties can
be seen in the aforementioned Table 3.
Examples of the production of weft yarns for tyre cord fabric
(Table Removed)


WE CLAIM:
1. A 100-400 dtex tyre cord fabric weft yarn comprising a heat-protected
nylon-6,6 multifilament, characterized in that the base yarn combines the
following features:
- 80% extension SLASE of 6 cN/tex to 12 cN/tex
- ultimate tensile stress elongation of 150 to 300%
- tenacity> 14 cN/tex
- reversibility limit of 5 cN/tex to 10 cN/tex
- 160°C thermal shrinkage force of 0.15 cN/tex to 0.8 cN/tex
- 160°C free shrinkage> 1%.
2. A weft yarn as claimed in claim 1, wherein the weft yarn combines the
following properties following a tensionless hot air treatment at 235°C for 5
min:
- ultimate tensile stress elongation of greater than 80%
- 80% extension SLASE of 6 cN/tex to 14 cN/tex
- reversibility limit of less than 10 cN/tex
- no increase in length due to the heat treatment.
3. A 100-400 dtex tyre cord fabric weft yarn substantially as herein
described with reference to the foregoing examples.

Documents:

1708-del-2005-abstract.pdf

1708-DEL-2005-Claims-(22-07-2008).pdf

1708-del-2005-claims.pdf

1708-DEL-2005-Correspondence-Others-(22-07-2008).pdf

1708-del-2005-correspondence-others.pdf

1708-del-2005-description (complete)-22-07-2008.pdf

1708-del-2005-description (complete).pdf

1708-del-2005-form-1.pdf

1708-del-2005-form-18.pdf

1708-DEL-2005-Form-2-(22-07-2008).pdf

1708-del-2005-form-2.pdf

1708-DEL-2005-Form-3-(22-07-2008).pdf

1708-del-2005-form-3.pdf

1708-DEL-2005-GPA-(22-07-2008).pdf

1708-DEL-2005-Petition-137-(22-07-2008).pdf


Patent Number 234544
Indian Patent Application Number 1708/DEL/2005
PG Journal Number 26/2009
Publication Date 26-Jun-2009
Grant Date 05-Jun-2009
Date of Filing 30-Jun-2005
Name of Patentee RHODIA FILTEC AG
Applicant Address CH-6021 EMMENBRUCKE, SWITZERLAND.
Inventors:
# Inventor's Name Inventor's Address
1 BURNO LANG WILHOFWEG 1, 6275 BALLWILL, SWITZERLAND.
2 PAUL SCHAFFNER WEINHALDE 12, 6010 KRIENS, SWITZERLAND.
PCT International Classification Number D02G 1/16
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA