DE3915819A1 - Making high grade core-sheath fibre yarn - Google Patents

Abstract

In core-sheath fibre yarn, with/without additional single component fibres, the core and sheath are produced by extrusion of spinning polymers and at least nearly all fibres have a complete sheath. In the yarn the proportion of core-sheath fibres A is expressed below as %, of which each core-sheath fibre is (M +/- 0.1 M) % of the total volume of the particular core-sheath fibre: A max. = 100, M min 0.5, and A min. 30 + (0.1 M power 8. The core fibres can be polyethylene-terephthalate or polyamide 46 and the sheath can be polyamide 66, a mixture of polyamide 66 and poly(m-xylylene-adipamide), polyethylene-terephthalate, or a mixt. of polyethylene-terephthalate and polyvinylidene-fluoride.

Description

The invention relates to a yarn of core-sheath threads, in the core and sheath of the core-sheath threads by extruding are prepared, and a method for its preparation.

Core-sheath threads and their manufacturing processes are many known. For example, in EP-A-00 11 954 thereon noted that special spinning devices required are to the appearance of so-called homofilaments even at never To avoid drigem coat proportion. Despite the avoidance of Gay threads by the known spinning device can not it is to be avoided that core-shell Threads are included that have a strongly fluctuating coat have portion, with even sections without jacket before come, and that in the yarn obtained the fluctuation the shell portion of the core-sheath threads strongly to each other fluctuates.  

Experiments have shown that with a spinning device according to EP-A-00 11 954 and a metered addition of core and sheath Material in the volume ratio of 85:15, as there in Bei 15% of the obtained core-shell Threads in the yarn, usually even less, a Mantelan Part of about 15%, even if you have the jacket portion considered a fluctuation range of ± 10%. The remaining Core-sheath threads in the resulting yarn have a larger size (up to 30% by volume) or smaller (to less than 5% by volume) Sheath share on.

In the known method, it is also not possible ge aims to obtain single or multiple homofilaments in the yarn. The genesis of gay threads is purely coincidental and it is also not guaranteed that in the yarn cross-section he visual home thread in Garnrichtung a Homofaden remains. Rather, changes in Garnlaufrichtung a Homofaden in a core-sheath thread and vice versa.

The large fluctuation of the shell portion causes everyone Thread in the yarn has different properties. This means that the threads in the yarn sway heavily with each other kende properties, which is undesirable.

In principle, yarns of core-sheath threads are the desired properties of the core material (strength, shrinkage, Elongation, birefringence, etc.), wherein the sheath other properties of the yarn (adhesiveness to others Materials, dyeability, grip, chemical or mechanical resistance, etc.). After the be knew procedures must have the average coat proportion 20 vol .-% and more are chosen to the fluctuation of Mantelanteils to keep within limits and the properties of the  Core material in relation to the total cross section of the core To obtain sheath thread reasonably evenly.

Object of the present invention is novel, Ge need more suitable yarns of core-sheath threads for Ver provide, if necessary, Einkomponentenfäden Homosexuals, where the core and sheath of the core Sheath threads produced by extrusion of spinnable polymers are placed, and at least almost all core-sheath threads have a complete coat. The yarns should be one better utilization of the properties of the core-shell Materials without deterioration of the properties of Ensure sheath material.

It is also an object of the invention to provide a method for producing to provide these yarns with one better uniformity of the yarns can be ensured and in the targeted and predictable the proportion of Ein component threads and the core-sheath threads (bicomponents threads) can be selected. The shell portion of the core Sheath threads should also below 20 vol .-% uniform can be achieved.

This object is achieved in that of all core-sheath threads in the yarn, the proportion of core-sheath threads A in%, of which each core-sheath thread (M ± 0.1 M )% sheath to total volume of the respective Core-sheath thread, while satisfying the following conditions:

A 100
M 0.5
A 30 + (0.1 M) ⁸.

The term M ± 0.1 M means that all core-sheath filaments are considered for the determination of A , which have M vol .-% sheath based on the total volume of the respective core sheath thread, wherein in determining the sheath portion M a Range of ± 10%. Since the conditions mentioned above must be fulfilled at the same time, it follows that M can only assume those values at which A does not exceed 100%.

In particular, yarns according to the invention have yarns in which

A 40 + 7 (0.1 M) ⁸ ,

prefers

A 50 + 100 (0.1 M) ⁸

applies, excellent properties.

Depending on the application, yarns,
in which at least 60% of the core-sheath threads have a sheath proportion M ± 0.1 M % by volume, where M is 9% by volume, or yarns,
in which at least 70% of the core-sheath filaments have a sheath proportion M ± 0.1 M , where 1% by volume M is 7% by volume, or yarns,
wherein at least 75% of the core-sheath filaments have a sheath proportion M ± 0.1 M , with 3% by volume M being 6% by volume, preferably.

Surprisingly, such yarns clearly ver improved specific properties. For example, the Specific strength (cN / dtex) in inventive Yarns are significantly higher than in the known yarns Core-sheath filaments, and also higher than monocomponent Yarns made only from the core polymer were.

The threads of the yarn according to the invention can virtually all have known cross-sectional shapes. For example For tire cords, threads with a round cross section are to be used while emphasizing light effects, the example may be desirable in carpet yarns, threads with trilobal cross section are preferred.

Certain properties of the yarn, such as detention ability to become particularly good at a yarn where the Threads, in particular the core-sheath threads, trilobal cross have cut.

As a polymer combination for core and cladding have be especially the following polymers proved:

core coat Polyethylene terephthalate (PET) Polyamide 66 (PA 66) Polyethylene terephthalate (PET) Mixture of polyamide 66 (PA 66) and poly (m-xylylene adipamide) Polyamide 46 (PA 46) Polyamide 66 (PA 66) Polyethylene terephthalate (PET) with high viscosity Polyethylene terephthalate (PET) with low viscosity Polyethylene terephthalate (PET) Mixture of polyethylene terephthalate (PET) and polyvinyl difluoride (PVDF)

Other favorable combinations are:

core coat Polyethylene terephthalate (PET) Polyethersulfone (PES) Polyamide 66 (PA 66) with high viscosity Polyamide 66 (PA 66) with low viscosity Polyamide 6 (PA 6) with high viscosity Polyamide 6 (PA 6) with low viscosity Polyethylene terephthalate (PET) Polytetrafluoroethylene (PTFE) Polyethylene terephthalate (PET) polyimide Polyethylene terephthalate (PET) Polyphenylene sulfide (PPS) Polyethylene terephthalate (PET) Polypropylene (PP) Polyethylene terephthalate (PET) Mixture of polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) Polyethylene terephthalate (PET) Mixture of polyethylene terephthalate (PET) and poly (m-xylylene adipamide) Polyamide 6 (PA 6) Polypropylene (PP) Polyamide 6 (PA 6) Polyvinyl difluoride (PVDF)

The yarns according to the invention find versatile application.

Sewing threads made of conventional polymers in the core (PET, PA 66, PA 6) can be coated with high temperature resistant polymers are, and are therefore for very high sewing speeds suitable. For ropes and nets of yarn, the coat can the chemical resistance, the UV resistance or the Improve temperature resistance.

For yarns for reinforcing elastomers, for example for tire cord used to reinforce pneumatic tires,  Driving belts or conveyor belts can be used through the coat of core-sheath threads an adhesion improvement between core and elastomer can be achieved. Also at Fiber reinforced plastics can do this in this way Adhesion between yarn and plastic improved become.

For carpet yarns can be over the sheath of the core-sheath threads the dyeability of the threads are improved, even if the Core of good conductive material to enhance the anti static properties, its color is often very dark and poorly dyeable with other colors. By Choice of different strongly shrinking material between Core and sheath material, when using such yarns for the production of carpets by heat in fer carpet or in textile products a significant Kräuse development of the yarns. Profiled yarns ver improve the light scattering. By special selection of the Sheath material of the core-sheath threads, the Brandver hold and / or the pollution behavior of such Core-coat threads produced carpets or textiles be significantly improved. Also mold or Lazy behavior can be reduced.

A hydrophobic coat can absorb moisture action can be effectively prevented by the core-sheath threads. This is particularly interesting when using the invention appropriate yarns in the textile sector. It is also possible be already mixed with color pigments polymer as Mantelkompo spun, causing spin-dyed core Sheath threads result.  

When using the yarns according to the invention in nonwovens can by appropriate selection of polymers the chemical Resistance improved, for example, in filter webs become. Also ion exchange properties can be achieved be affected or the fire behavior.

The object of the invention is also achieved by a Process for producing the yarns according to the invention in a conventional manner (EP-A-00 11 954) the core component over a first spinneret plate of a second Spinneret plate is supplied in several individual streams, wherein between the first and the second spinneret plate each core component single stream flowing around this Sheath component is supplied, both components in common spun, stretched and wound up, which is itself characterized in that at least by the area of Single streams of the core component around the shell component is exposed to a flow resistance.

The process according to the invention can be carried out in one stage (without Intermediate rewind) or multi-level (with intermediate winding).

As a flow resistance is particularly suitable a mesh braid, which has a hole for each individual flow. It is favorable, if the mesh weave the whole Interspace between first and second spinneret plate with the exception of the holes for the individual streams. Also other flow resistance such as porous Plates can be used. Through the mesh can also with spinneret plates larger dimensions of Distance between the two spinneret plates everywhere the same  kept large because the mesh at the same time serves as a spacer plate.

In a simple way, this can also be achieved that targeted core-sheath threads can be produced by Thread to thread have different shell portion. For this purpose, different for the individual core streams Resistors selected for the sheath currents. Will the cons stood so high that a flow around the mantle materials to a special core current is omitted causes Einkomponentenfäden in a simple manner.

Meshes which have proven particularly successful are those which are commercially available under the name RVS X mesh, where x is from 30 to 500. Here, RVS means that it is stainless steel, while x- mesh means that x wires per inch can be chosen in both directions in the wire, the wires being woven together and having a diameter of 0.5 to 0.025 mm.

The flow resistance can also be determined by the permeability of the body used as a flow resistance. Here, the permeability K is defined with

in which
η the viscosity of the liquid used in Pa · s,
V is the velocity of the liquid used by the flow resistance in m / sec,
δ p / δ x the pressure gradient in N / m³ in the flow direction.

This results in the permeability in m ² .

The permeability K of the flow resistance to be used is preferably between 10 ^-11 to 3 × 10 ^-10 m ² .

It is particularly surprising that the inventive Method both in melt spinning and in the Solvent spinning can be applied, as well Both types of spinning can be combined. For example Both components can be made by melt spinning or solution spiders are produced. It can also be at For example, the core component by melt spinning and the Sheath component can be produced by solvent spinning. Solvent spinning means that the spinning solution from a dissolved in solvent polymer, while the Melt spinning a molten polymer is used.  

If in the first and second spinneret plate only respectively a spinnerette opening is provided, can with the Process according to the invention, a core-shell monofilament produced by a coat of very uniform thickness over the circumference and over the length of the Core-coat-monofilament distinguishes.

The invention is based on the following figures and Examples explained in more detail.

According to figures is shown:

Fig. 1, the area is accessed for the inventive yarns over the prior art,

Fig. 2 is a prinizpielles process scheme for producing the yarns according to the invention,

Fig. 3 schematically illustrates the structure of a spinneret as used in the prior art,

Fig. 4 schematically illustrates the structure of a spinneret which is required for performing the method according to the invention,

Fig. 5 and 6. The construction of the spinneret according to Figure 4,

Fig. 7 shows a partial cross section of a yarn according to the prior art,

Fig. 8 is a partial cross-section through an inventive yarn.

In Fig. 1 it is shown, which area can be developed by the yarns according to the invention from core-sheath threads. It shows a diagram in which on the abscissa of the shell portion in Vol .-% and on the ordinate, the proportion A in% of the core-sheath threads with a shell proportion M ± 0.1 M of all core-sheath threads in the yarn are applied. The possible distribution in the state of the art results from the hatched area designated as state of the art. It follows that it was readily possible in the prior art to produce yarns of core-sheath threads with a proportion of 25% shell, in which all core-sheath threads a coat proportion of 25%, while in a yarn With core-sheath threads with a sheath proportion of 10%, only 5% had a sheath proportion of 10%. According to the invention, it has now been possible to provide yarns with significantly improved uniformity. Here, curve A corresponds to the conditions according to claim 1, curve B to the conditions according to claim 2, and curve C to the conditions according to claim 3.

In Fig. 2 is a schematic principle schematically scheme for producing the yarns of the invention Darge presents. Here, 1 designates a spinneret pack to which a spinneret plate combination 2 is flanged, which is explained in more detail below with reference to FIGS. 3, 4, 5 and 6. The spinneret package 1 are preceded by extruder and melt lines in the usual way (not shown in the figure). After leaving the spun core-jacket or homofilaments 8 , these pass through a cooling shaft 7 , which is fed with cooling air 9 . About a preparation roller 5 , the threads are combined and fed to a drawing unit 3 , 4 and then wound onto a bobbin 6 as a finished yarn.

In Fig. 3 is a detail of a known from the prior art spinneret is shown, in which a first spinneret plate with 10 and a second spinneret plate 11 is designated. The core melt stream is fed via spinnerets 12 through the first spinneret plate 10 of the second spinneret plate 11 , thereby discharging into the Spinndüsenkelch 13th The sheath flow flows into the gap between the nozzle plate 10 and 11 and thus flows around each coming from a nozzle 12 core stream. In this way, each core component single stream is supplied to the jacket component by flowing, after which both components jointly flow through the nozzle cup 13 into the spinning nozzle opening 14 , from which these are extruded. In the region in which the sheath flow flows around the core stream, elevations 15 are provided on the second nozzle plate 11 .

In Fig. 4, the structure of a spinneret is shown schematically, as it finds in the inventive method Ver use. A first spinneret plate is denoted by 20 , a second spinneret plate by 21 . The supply of the core component via opening 26 in a nozzle channel 22 , which continues in the second nozzle plate 21 as a channel 23 . The jacket component is distributed over annular channels 28 between the nozzle plate 20 and 21 evenly, wherein the gap between the nozzle plate 20 and 21 is filled with a metal wire mesh 27 such that the nozzle channels 22 and 23 remain continuously free. The jacket component is thus supplied from the annular channel 28 via the metal wire mesh 27 of the core component flowing around. In this case, the metal wire mesh acts on the jacket component as a flow resistance. Core and shell component are jointly spun over the nozzle 24 .

Fig. 5 and 6 shows an embodiment of a spinneret, as it is used for the inventive method, wherein Fig. 5 is a longitudinal section and Fig. 6 shows a cross section. Via channel 32 , the core component of the first spinneret plate 20 is supplied while the jacket component via channel 33 (continuation is shown in phantom because channel 33 runs outside the plane ver) on its continuation 34 through the first spinning nozzle plate 20 into the annular channels (not designated ) is guided between the first and second spinneret plate. Between the first nozzle plate 20 and second nozzle plate 21 , the flow resistance 27 is inserted, which plate 20 and 21 simultaneously acts as a spacer between the first and second nozzles. With 31 are centering pins and labeled with 30 seals. Bushings 35 prevent leakage of the jacket component between the channel plate 29 and the first spinneret plate 20th

In Fig. 7 is a partial cross section of a yarn of core-sheath threads is shown, as it is available according to the prior art. The jacket is designated 37 and the core 36 . It can be seen that both core and cladding surfaces vary widely from yarn to yarn. Also, over the length of the individual threads can be found very different shell and / or core surfaces.

FIG. 8 shows a corresponding partial cross section of a yarn according to the invention. Here, the uniformity of the core surface 38 and lateral surface 39 falls on.

The invention will be explained in more detail by means of examples.

Examples 1 to 9

Examples 1 to 9 show the variation width, within which the yarns according to the invention are produced can.

In Examples 1 to 3, a core polymer was a polyester with a typical relative to textile yarns viscosity (1 g of polymer in 100 g of m-cresol, measured at 25 ° C), in the Examples 4 to 6 a polyester with a technical Yarns low relative viscosity, and in the examples 7 to 9 a high viscosity polyester such as For example, used for tire cord or for sewing threads is selected. In all cases was used as sheath material Polyamide 66 (PA66) used.

Within each of the above-mentioned example groups, the spinning pump throughput of core and sheath component was varied in each case. As a flow resistance, a mesh "RVS 60 mesh rolled" was used (for further description, see Example 10 to 15). The spinneret used corresponded to that shown in FIG. 4 to 6.

The core-sheath threads were prepared by a method Herge, as explained in more detail above with reference to FIG. 2. However, a stretching was omitted. The process conditions and the polymers used are shown in Table 1. Furthermore, in Table 1, indicate how many percent (A (%)) of the core-sheath filaments M vol .-% sheath (taking into account all core sheath threads, have the (M ± 0.1 M )% sheath) on the total volume of the respective thread. The figure of A (%) is a statistical average of 10 cross-section measurements at different points of the respective yarn.

The values of A prove the uniformity with which the yarns according to the invention can be made available, whereby the diameters D of the individual core-sheath threads in the yarn can also be described as very uniform, since these also have a range of approximately (D. ± 0.1 D ).

Table 1

Examples 10 to 15

According to Examples 10 to 15 are different tire cords produced and their properties are determined.

For this purpose, the core polymer was a polyester with a rela viscosity of 2.04. As sheath material was in Examples 10 and 11 polyamide 66 (PA66) and in the Examples 12 to 15 a mixture of polyamide 66 and 0.3 Weight% poly (m-xylylene adipamide) (in the table with "PA66 + Additive ") .This mixture has a particularly good adhesion to polyester as well opposite to elastomeric materials, in particular rubber, on.

Each core-shell combination was wound up once at 900 m / min and once at 500 m / min without stretching, again performing a process as shown in FIG . The flow resistance used was a mesh with the designation "RVS 60 mesh rolled". So this mesh was made of stainless steel wires. Both longitudinally and transversely, 60 wires per inch were interwoven. The commercially available mesh braid contained 0.16 mm diameter steel wires.

The spinneret used corresponded to that shown in FIG. 4 to 6.

Examples 14 and 15 became direct in the procedure Keeps the spinneret a 0.4 m long heating pipe to He tion of a delayed cooling used. The chosen ones Process conditions are shown in Table 2.  

Table 2

The resulting yarns were then on a Ver Stretching machine stretched. Here, the yarn ran from the spinning coil into a first trio. From the trio the yarn was over Septet fed to a second trio and then through a 10 m long steam treatment line in which the yarn is steamed treated at a temperature of 250 ° C, a third Trio fed and then in compliance with the stretching speed wrapped up. The septet was at a temperature kept at 75 ° C.

The selected for the yarns according to Example 10 to 15 stretch ratios and stretching rates are from Table 3 seen. Here stretch ratio means septet Draw ratio, with which the yarn when passing through the Septets was applied. The total draw ratio results from the speed difference between first and third trio.  

Table 3

The properties of the yarn thus obtained are under "Yarn" in Table 4. LASE means 1% (N) the strength of the yarn in (N) at a given Elongation of 1% (Load at specific elongation). The same applies to LASE 2% and LASE 5%.

HAS 4 '/ 160 ° C (hot air shrinkage 4 min at 160 ° C) gives the Hot air shrinkage of the yarn when the yarn is 4 min under a Load of 5 m N / tex exposed to a temperature of 160 ° C. becomes.

The resulting yarns each became a tire cord of the Construction 1100 (Z 472) × 2 (S 472) stranded. The own the tire cord with this construction are under the Designation "cord" also listed in Table 4.

The cord obtained in this way was in the usual way with an adhesive layer provided. Hereby, the cord came in behind 120 seconds through an oven with a temperature of 150 ° C. under a tension of 5 N, through a bath, and through 45 sec an oven with a temperature of 240 ° C under a tension led by 5N. The bath contained the following components:

Demineralised water,
caustic soda,
resorcinol,
Formaldehyde,
VP latex,
Ammonia.

The properties of the cord prepared in this way are under "dotted cord" also listed in Table 4.

The values for A and M were identical for the yarn, the cord and the dipped cord, so these values are only listed under "Yarn".

Table 4

Claims (19)

Yarn of core-sheath threads and possibly further one-component threads, in which the core and sheath of the sheath-core threads are produced by extrusion of spinnable polymers, and at least almost all sheath-core threads have a complete sheath, characterized that of all core-sheath threads in the yarn, the proportion of core-sheath threads A in%, of which each core sheath thread (M ± 0.1 M) % sheath on the total volume of the respective core-sheath thread on at the same time satisfies the following conditions: A 100
M 0.5
A 30 + (0.1 M) ⁸. A yarn according to claim 1, wherein: A 40 + 7 (0,1 M) ⁸ . A yarn according to claim 1, wherein: A 50 + 100 (0.1 M) ⁸ . 4. Yarn according to claim 1, characterized in that at least 60% of the core-sheath threads have a sheath portion (M ± 0.1 M) , wherein M is 9 vol .-%. 5. Yarn according to claim 1, characterized in that at least 70% of the core-sheath threads have a sheath portion (M ± 0.1 M) , wherein 1 vol .-% M is 7 vol .-%. 6. Yarn according to claim 1, characterized in that at least 75% of the core-sheath threads have a sheath portion (M ± 0.1 M) , wherein 3 vol .-% M is 6 vol .-%. 7. Yarn according to one or more of claims 1 to 6, characterized in that in the core-sheath threads the core of polyethylene terephthalate (PET) and the Sheath made of polyamide 66 (PA 66). 8. Yarn according to one or more of claims 1 to 6, characterized in that in the core-sheath threads the core of PET and the coat of a mixture of PA 66 and poly (m-xylylene adipamide) exists.   9. Yarn according to one or more of claims 1 to 6, characterized in that in the core-sheath threads the core consists of PA 46 and the coat of PA 66. 10. Yarn according to one or more of claims 1 to 6, characterized in that in the core-sheath threads the core is made of high viscosity PET and the sheath off PET with low viscosity exists. 11. Yarn according to one or more of claims 1 to 6, characterized in that in the core-sheath threads the core of PET and the coat of a mixture of PET and PVDF exists. 12. A method for producing a yarn according to one of preceding claims, wherein the core component via a first spinneret plate of a second spin nozzle plate is supplied in several individual streams, wherein between the first and second spinnerets plate each core component single stream around it flowing the shell component is supplied, both Components spun together, stretched and on be wound, characterized in that at least around the region of the individual streams of the core component the shell component out a flow resistance is set. 13. The method according to claim 12, characterized in that used as a flow resistance mesh mesh is, which for each single stream on a hole has.   14. The method according to claim 12 or 13, characterized in that a flow resistance is selected, which has a permeability between 10 ^-11 and 3 · 10 ^-10 m ² . 15. The method according to claim 13, characterized in that the mesh has 30 to 500 wires per inch. 16. The method according to one or more of claims 12 to 15, characterized in that for the production of Homofilaments of the resistance is chosen so high that in the intended for the production of homofilaments Single streams a flow around the shell component omitted. 17. The method according to one or more of claims 12 to 16, characterized in that shell and / or core Component is melt spun. 18. The method according to one or more of claims 12 to 16, characterized in that shell and / or core Component dissolved in a solvent spun becomes. 19. The method according to one or more of claims 12 to 18 for the production of core-sheath filaments, characterized characterized in that a first and a second spinning nozzle plate is used, each only one nozzle opening has.