EP0980447B1 - Filling yarn and method for producing it from thermally protected polyamide 6.6 for tyre cord fabric - Google Patents

Description

The present invention relates to a weft yarn a heat-protected polyamide 6.6 multifilament for Tire cord fabric with a total titer of 100-400 dtex, and a method for producing a weft yarn.

Weft yarn for tire cord fabric and a process too its production from polyester POY are known (WO-A-96/2391). Made from polyester POY filaments Yarns have a very low thermal resistance on. An improvement does not occur with deeper ones either Spinning speeds on. On the relaxation heater the filament thread becomes brittle and loses at 220 ° C much of its strength and residual elongation.

The object of the invention is a PA 66 weft for To provide tire cord fabric, which is a high thermal stability, a defined reversibility limit, sufficient strength and sliding resistance as well as a high maximum tensile strength having.

Another task is to develop a method for To provide weft yarns for tire cords which, after impregnation, have a maximum tensile strength stretch point out the spreading of the cords in tire manufacture without weft breaks guaranteed.

• einen spezifischen LASE (SLASE) bei 80% Dehnung von 6 cN/tex bis 12 cN/tex
• eine Höchstzugkraftdehnung von 150 % bis 300 %
• eine Festigkeit von > 14 cN/tex
• eine Reversibilitätsgrenze von 5 cN/tex bis 10 cN/tex
• eine Thermoschrumpfkraft bei 160°C von 0.15 cN/tex bis 0.8 cN/tex
• eine Freie Schrumpfung bei 160°C > 1 %

According to the invention, the object is achieved in that the raw yarn simultaneously has:

• a specific LASE (SLASE) at 80% elongation from 6 cN / tex to 12 cN / tex
• a maximum tensile force stretch of 150% to 300%
• a strength of> 14 cN / tex
• a reversibility limit of 5 cN / tex to 10 cN / tex
• a thermal shrinkage force at 160 ° C from 0.15 cN / tex to 0.8 cN / tex
• free shrinkage at 160 ° C> 1%

Such a yarn has the advantage that it pronounced flow behavior in the fabric, when building a Tires, a homogeneous warp thread distribution enables. In addition, this yarn has succeeded in making a To provide single component weft yarn that no annoying and dangerous when weaving Dust generation, like that when using natural fibers is common causes. It is also said to be high Can hardly withstand thermal stress during impregnation have a width increase and when building a Tires a very homogeneous cord warp spread enable and so universal for tire cord fabric based on nylon, polyester and aramid become.

For an elongation of 80%, preferably 90-150% a load of 6 cN / tex to 12 cN / tex, preferably 6-10 cN / tex, proven to be useful. Elongation forces higher than 12 cN / tex have the disadvantage of one inhomogeneous warp thread distribution when expanding the Radial tire on the tire building machine. Tensile forces under 6 cN / tex lead both with large and with selective loads, for example when storing the Fabric bales, for irreversible weft stretching and thereby insufficient stability with respect Kettfadenparallelität. This results in bad to unusable tire carcasses.

A maximum tensile elongation of <300%, preferably 180-280 % has proven to be useful. Ultimate tensile strain of more than 300% lead in manufacturing from tire cord fabrics under normal loads to one too high stretch; a maximum tensile elongation of however, less than 150% leads to an insufficient Elongation reserve, resulting in insufficient Weft deformation or even weft breakage in the Tissue. In both cases, the resulting ones Tire carcasses are inhomogeneous and therefore also those from them manufactured tires.

It is appropriate that the weft have a firmness of at least 14 cN / tex, so that the load peaks containing different process stages cannot lead to weft breaks.

A reversibility limit of 5 to 10 cN / tex is particularly advantageous. A reversibility limit smaller than 5 cN / tex leads to dimensional stability in the weft insertion and the fabric width stability up to cannot be guaranteed for processing in the tire. With a reversibility limit greater than 10 cN / tex is sufficient the force resulting from vulcanization is not sufficient to spread the individual cords evenly.

A thermal shrinkage force of 0.15 to 0.8 cN / tex has that Advantage that the fabric width when impregnating the Fabric practically does not jump in and therefore here too a homogeneous cord chain distribution, especially with Fabrics with weft yarn inlay edges, is guaranteed; with a thermal shrinking force greater than 0.8 cN / tex results, despite the impregnation with Holding rollers acting on the weft threads, a thread shortening, making the required Homogeneity is not ensured. This leads to, especially undesirable on the fabric edges Kettfadenverdichtungen. With thermal shrinkage forces of less than 0.15 cN / tex can be used for thermal Stress (impregnation) of the carcass fabric already a thread elongation occur, whereby the Parallelism of the warp threads is no longer guaranteed.

According to the invention, it is absolutely necessary that all Characteristics of the raw yarn simultaneously in the claimed There are limits.

• eine Höchstzugkraftdehnung von grösser 80 %
• einen SLASE bei 80% Dehnung von 6 cN/tex bis 14 cN/tex
• eine Reversibilitätsgrenze von 5 bis 10 cN/tex
• Keine unkontrolierbare Längenverenderung durch die Temperaturbehandlung

It is expedient that the weft yarn has all the following characteristics at the same time after 5 minutes of hot air treatment without tension at 235 ° C.

• a maximum tensile force expansion of more than 80%
• a SLASE at 80% elongation from 6 cN / tex to 14 cN / tex
• a reversibility limit of 5 to 10 cN / tex
• No uncontrollable change in length due to the temperature treatment

Maximum tensile force strains greater than 80%, preferred larger than 110% are appropriate. Elongation at break of more than 110% on the impregnated weft yarn have proven to be particularly suitable because the process-related spreading of the carcass a random Breaking individual weft threads, especially when expanding the green tires on the tire building drum prevented becomes. Scattered weft breaks lead to uneven Cord spacing in the carcass and thereby insufficient concentricity of the tires.

The weft yarn also has one after impregnation SLASE 80%, less than 14 cN / tex, preferably less than 12 cN / tex. A SLASE 80% of more than 12 cN / tex increases the risk of uneven when building a tire Distribution of the warp threads when expanding the carcass to the final tire circumference. The impregnated yarn is RFL dipped in a known manner and then heat-set at Temperatures up to 245 ° C, preferably at 210-235 ° C and during 45-200 s.

The reversibility limit is also after the hot air treatment less than 10 cN / tex, preferably less than 8 cN / tex. This has the advantage that the Vulcanizing spreading forces that suffice To deform weft threads so that an even Distribution of the carcass threads is ensured.

As the starting material for the raw yarn of the invention The process used is a polyamide 6.6 LOY. Instead of A pure polyamide 6.6 can also be used with a copolyamide at least 85% by weight can be used. As copolyamide PA 6, PA 6.10 and aramid, for example, are suitable. The PA-6.6-LOY is usually at spinning take-off speeds stretched at less than 1800 m / min Service. The starting yarn is with a copper additive at least 30 ppm Cu, preferably with 60-80 ppm Cu thermally protected.

Has proven particularly suitable for the single-stage Manufacturing, starting from a LOY, a process proven to be heat protected with at least 30 ppm Cu Polyamide 6.6-LOY filaments between 10 and 200%, preferably between 40 and 150%, in particular between 40 and 125 are stretched, then by means of a Compressed gas to at least 10 knots / m, preferred at least 15 knots / m. The procedure has the advantage that a compact fibril composite with relatively rough and non-slip surface results. The drawing of the LOY yarn can be cold or warm, with or without a stylus.

In a varied process, the polyamide LOY filaments in a first step between 10 and stretched 200% and then in a second Method step using a compressed gas to at least 10 knots / m simultaneously or subsequently swirled, at a temperature between 150 and 235 ° C, preferably 200 and 225 ° C between 0-30% relaxed. That has the Advantage that lower shrinkage values and lower Reference forces (LASE) result.

In a further variant of the method, the Weft yarn additionally at a temperature between 150 and 235 ° C, in particular between 180 and 225 ° C by 0 to 10% fixed or stretched. That has the advantage, that achieved a further reduction in shrinkage values and thus shrink properties the respective Process conditions in tire construction are adjusted can.

The weft yarn is used as raw yarn and is especially suitable for tire cord fabrics.

Measurement Methods:

Carried out generally after 24 h storage of the coils in the Standard climate 20 ± 2 ° C and 65 ± 2% RH

titers:

Determination of the fineness of yarns and twists after the Weif procedure (DIN 53 830 part 1).

Tensile test:

• Einspannlänge 100 mm
• Prüfgeschwindigkeit 1000 mm/min.

Simple tensile test on yarns and twists in an air-conditioned state (DIN 53 834 part 1)

• Clamping length 100 mm
• Test speed 1000 mm / min.

Module:

Slope of the quasi-linear increase in the initial KD range.

reversibility:

Synonymous with the elastic limit ⇒ load, in which the transition from the reversible to the irreversible expansion range occurs.

SLASE:

Resulting strength in cN / tex at defined Strains (2%, 5%, 10% and 80%).

Free thermal shrink: (residual or permanent)
Remaining change in length in% after a hot air treatment at 160 ° C that is free of thread tension for 15 minutes and then cooling and conditioning in a standard climate for 15 minutes.

Effective shrinkage:

Length change in% during the exposure to temperature 15 min treatment at 160 ° C and 0.1 cN / tex preload.

Effective shrinkage:

Due to the hot air heat effect of 160 ° C during 15 min resulting force change in cN / tex one at 0.1 cN / tex specimen firmly clamped on both sides. The Measurement takes place during the exposure to temperature.

The invention is intended to be illustrated in more detail by means of examples to be discribed.

Examples 1:

A polyamide 6.6 with a Cu content of 60 ppm was in a known manner to a LOY, dtex 519, 34 Fibrils, with those listed in the table below Properties spun. This source material was then at a take-off speed of 450 m / min (take-off godet in the stretching zone) by 125%, with Drawing pen, cold drawn and with a titer of 224 dtex wound. The detailed yarn properties can be seen from Table 1 mentioned.

Example 2:

A polyamide 6.6 with a Cu content of 30 ppm was in a known manner to a LOY, dtex 550, 17 Fibrils, with those listed in the table below Properties spun. This source material was then at a take-off speed of 60 m / min (take-off godet in the stretching zone), at 160 ° C, without Straightening pen, stretched by 100% and with a titer of 290 dtex wound. The detailed yarn properties can be seen from Table 1 mentioned.

Example 3:

A polyamide 6.6 with a Cu content of 60 ppm was in a known manner to a LOY, dtex 252, 34 Fibrils, with those listed in the table below Properties spun. This source material was then at a take-off speed of 120 m / min (take-off godet in the stretching zone) by 40%, with Drawing pen, cold drawn and with a titer of 190 dtex wound. The detailed yarn properties can be seen from Table 1 mentioned.

Example 4:

A polyamide 6.6 with a Cu content of 60 ppm was in a known manner to a LOY, dtex 252, 34 Fibrils, with those listed in the table below Properties spun (analogous to Example 3). This Starting material was at a take-off speed from 143 m / min (take-off godet in the stretching zone) by 50%, with stylus, cold stretched. In another continuous process stage was carried out by means of Contact heater of 25 cm in length, at a temperature of 220 ° C, a 25% relaxation. The one after these Treatments resulting thread titer is 215 dtex. The detailed yarn properties are from the mentioned Table 2 can be seen.

Example 5:

A polyamide 6.6 with a Cu content of 60 ppm was in a known manner to a LOY, dtex 273, 34 Fibrils, with those listed in the table below Properties spun. This source material was then at a withdrawal speed of 390 m / min (deduction godet in the stretching zone) by 11%, without Drawing pen, cold drawn and with a titer of 243 dtex wound. The detailed yarn properties can be seen from Table 2 mentioned.

Example 6:

A polyamide 6.6 with a Cu content of 60 ppm was spun in a known manner into a LOY, dtex 252, 34 fibrils, with the properties listed in the following table (analogously to Example 3).
This starting material (LOY) was then cold-drawn in a first stage at a take-off speed of 135 m / min (take-off godet in the draw zone) by a draw pin. In the second continuous process stage, a convection heater of 65 cm in length, at a temperature of 220 ° C, was used to relax 25%. In the third continuous process step, the material was post-fixed on a contact heater of 25 cm in length at 210 ° C without delay. The thread titer resulting from these treatments is 214 dtex. The detailed yarn properties are shown in Table 2 mentioned.

Example 7 (relaxation series):

A polyamide 6.6 with a Cu content of 60 ppm was spun in a known manner to a LOY, dtex 519, 34 fibrils, with the properties listed in the following table (analogously to Example 1).
This starting material (LOY) was then cold-drawn in a first stage at a take-off speed of 80 m / min (take-off godet in the drawing zone) by a drawing pin. In a second continuous process step, three variants with 5%, 15% and 25% relaxation were produced using a convection heater of 65 cm in length and at a temperature of 225 ° C. The thread titers resulting from these treatments are between 283 and 349 dtex. The detailed yarn properties are shown in Table 3 mentioned.

Example 8 (supplement to Example 7):

The 25% relaxation variant described in Example 6 was additionally fixed in a third process step in a contact heater of 25 cm in length at 210 ° C. without delay. The thread titer resulting from this treatment is 343 dtex. The detailed yarn properties are shown in Table 3.

Claims (5)

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 according to Claim 1, characterized in that the weft yarn combines 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 less than 10 cN/tex

   no increase in length due to the heat treatment.
3. A process for producing a 100-400 dtex tyre cord fabric weft yarn comprising a heat-protected nylon-6,6 multifilament, characterized in that nylon LOY filaments are drawn between 10 and 200% and entangled to at least 10 nodes/m by means of a compressed gas.
4. A process according to Claim 3, characterized in that the nylon LOY filaments are drawn between 10 and 200% in a first process step and then entangled to at least 10 nodes/m by means of a compressed gas and relaxed by between 0 and 30% at 150 to 235°C in a second process step.
5. A process according to Claim 4, characterized in that the nylon LOY filaments are additionally set (afterdrawn) between 0 and 10% at 180-230°C.