EP0010229B1 - Method and apparatus for texturising multifilament yarns - Google Patents

Abstract

A process for texturizing bundles of filaments of synthetic high molecular weight materials at high speed, wherein the filament bundle is passed through a feed nozzle and is then brought into contact with a hot gaseous medium which is undergoing a vortical motion and has acquired a vortex angle of from 10 DEG to 70 DEG as a result of passage through a vortex chamber, is then heated by the fluid medium in a downstream tubular chamber and is subsequently fed to an expansion stage to produce the crimp, and apparatus for carrying out this process.

Description

The present invention relates to a method for texturing bundles of threads and a device suitable therefor.

Basically, it is known that you can curl and swirl bundles of synthetic high molecular weight substances by passing the bundles of threads through an inlet nozzle, then allowing them to meet with a hot flowing medium, heating them up to the plasticizing temperature through a tubular chamber and then into an expansion zone Ruffles and possibly swirling conducts. A suitable device is described in DE-B-20 06 022, for example, the expansion zone being in the form of a tube with longitudinal slots. It is also known that the hot flowing medium is fed through a centering body for the tubular chamber in the nozzle (cf. DE-B-20 06 022). It is also known that the hot flowing medium is given a swirl (DE-A-26 32 384).

A method has now been found for texturing bundles of threads made of synthetic high-molecular substances at high texturing speeds, in which the bundle of threads is passed through an inlet nozzle, meets a hot, gaseous medium which is in a swirling motion and is heated by this medium in a subsequent tubular chamber is and then fed to the crimp an expansion stage in which the hot, swirling flowing medium is given a swirl angle of 10 to 70 °, preferably 20 to 50 °, by guides in a swirl device, the swirl angle being the angle between the tangent to a helix, which results from twisting a previously straight surface line of a cylinder (or cone), and which defines a tangent-crossing parallel to the central axis of the system.

It is surprising that not only is a crimped and intermingled yarn obtained as expected, but that it also has a better crimp value than a textured yarn which has been produced analogously but without a twist with the specific twist angle. Another advantage results from the fact that the process can be carried out at somewhat lower temperatures than can be used in a process without the specific swirl movement. Surprisingly, the yarn pull-in tension in front of the yarn inlet nozzle increases by a factor of 2 and even higher under the effect of the directed twist. Therefore, a roving with a small proportion of loops can be processed without any problems, which leads to disturbances in a process without the specific twisting movement of the hot flowing medium.

The invention also relates to a device for texturing bundles of threads made of synthetic high-molecular substances consisting of an inlet nozzle for the bundle of threads, one or more feeds for a hot flowing medium to the bundle of threads, the feeds being designed in such a way that they give the flowing medium a twist , a subsequent tubular chamber, in which the bundle of threads is heated by the hot gaseous medium, and an expansion stage, in which one or more swirlers are arranged in the feeds for the hot flowing medium, which have guides designed such that the hot flowing medium receives a swirl angle of 10 to 70 °, in particular a swirl angle of 20 to 50 °, the swirl angle being defined as above. A device as it is considered suitable is shown schematically in FIG. 1, FIGS. 2 to 3 show details.

The device consists of an inlet nozzle 1 (sometimes also called a thread insertion tube), a feed 2 for the hot flowing medium 9 with a swirl sensor 3, a tubular chamber 4 (sometimes also called a thread guide channel or thread guide tube) and an expansion stage 5, in FIG. 1 as Slotted nozzle shown. An embodiment of the swirl generator 3 is shown in FIG. The hot flowing medium is formed through the channels 6- here as grooves --- which are arranged at an angle of 10 to 70 °, in particular 20 to 50 °, shown here by 45 °, to the direction of movement of the thread bundle. The channels 6 in the swirl sensor 3 can have, for example, square or rectangular cross sections; these embodiments can be produced particularly easily if they are milled as grooves in the swirl body, which also serves as a centering body, the grooves then forming channels with the outer tube 7 of the nozzle. The swirling at the desired angle can, however, also take place through channels 11 with a round or oval cross section, as e.g. are shown schematically in FIG. But you can also attach simple baffles, straight or curved. The swirl sensors are to be designed according to the invention so that the hot flowing medium has a swirl angle of 10 to 70 °, in particular 20 to 50 °, practically at such an angle with respect to the imaginary axis of the inlet nozzle or the tubular chamber flows because these are normally arranged coaxially and the flowing medium flows around this chamber.

The cross sections of the channels 6, 11 in Swirl sensors 3 are variable within wide limits. However, it is advantageous if they are arranged symmetrically around the tubular chamber 4 and the free area is 1/4 to 3/4 of the annular area between the outer tube 7 of the nozzle and the tubular chamber 4. This circular ring area represents the free cross-sectional area around the yarn guide tube. The number of channels in the swirl device is expediently 4 to 12 pieces, preferably 6 to 10 pieces. Even if the number is not essential to the invention, there is an advantage with a number of 6 to 10 channels. With fewer channels, their effect wears off; with significantly more channels of correspondingly smaller dimensions, the prefabricated. more expensive.

All common metals or alloys of sufficient temperature and corrosion resistance can be used as the production material for the nozzle and the swirl generator 3. Have special. Proven stainless steels. Of course, other metals can also be used insofar as they meet the thermal-corrosive requirements.

The channels determining the swirl direction form an angle with respect to the longitudinal axis, the channels being able to lie on the jacket of a cylinder intended around the longitudinal axis of the tubular chamber or on a cone jacket, so that the channels incline towards this longitudinal axis or also from it lean away. In other words, the hot flowing media can meet on a smaller or a larger circle than that which corresponds to the average radius of the annulus between the outer tube 7 and the radius of the tubular chamber 4. The swirl sensor 3 can e.g. at a distance which corresponds to the inner diameter of the outer tube 7, from the junction of the flowing medium and the running bundle of threads 8, but it can also, if less effectively, be at a greater distance, e.g. 3 to 4 times the inner diameter of the outer tube 7, be arranged from this union. The dimension of the texturing nozzles used are not changed by the device according to the invention. For example, devices known from DE-B-20 06 022 or DE-B-23 31 045 with the dimensions specified there are quite suitable. The ratio of the inside width of the inlet nozzle 1 (the thread introduction tube) to the inside width of the tubular chamber (the thread guide tube) 4 is expediently 1: 1.0 to 1: 4, advantageously 1: 1.4 to 1: 2.2. The diameter ratio and the dimensions themselves depend on the thickness of the thread bundles to be crimped. In general, it is expedient not to select the clear widths larger than necessary for the yarn transport in order to keep the consumption of the flowing medium low. Have proven themselves for the inlet nozzle e.g. at 1,300 dtex diameter from 1.1 to 1.3 mm. Inlet nozzle 1 and tubular chamber 4 are primarily arranged coaxially at a distance of 0.1 to 3.0 times, preferably 0.8 to 1.4 times the outer diameter of the thread guide tube 4, in the specific case approximately at a distance from 0.3 to 1 mm, preferably from 0.4 to 0.5 mm. The tubular chamber 4 is followed by an expansion zone which, when configured as a slot nozzle, can have the same internal width as the tubular chamber. But it can also change suddenly or gradually to a larger diameter. 4 to 18 slots with a slot width of 0.3 to 1.0 mm, in particular 0.4 to 0.5 mm, have proven themselves in the slot nozzle. However, other devices can also be used which have the elements inlet nozzle, annular gap, tubular chamber and expansion zone. The process conditions known for the respective nozzles also apply with regard to the relationship between the temperature of the heating medium and the type of thread bundle. However, it has been found that, according to the invention, temperatures of the hot flowing medium which are generally 10 to 20 ° lower than those used without the specific swirling can be used. The procedure can generally be described with reference to FIG. 1 as follows: the bundle of threads 8 is fed into the texturing nozzle via the inlet nozzle 1, the flowing medium 9 is fed into the gap 10 between the inlet nozzle 1 and the tubular chamber via the feed 2 and the swirl device 3 4 led. The swirl sensor 3 causes the flowing medium to swirl which, due to the shape of the swirl sensor, leads to a swirl angle of between 10 and 70 ° on the thread guide tube or on the thread bundle. In the drawn device, it is approximately 45 °. The range from 20 to 50 ° has proven to be particularly advantageous because the properties of the crimped yarn in terms of crimp value, tensile strength and elongation at break are in a particularly favorable range.

The further run of the thread bundle through the tubular chamber 4 and the expansion zone runs as usual.

In the present context, bundles of threads are understood to mean endless structures made of individual threads, the individual threads also being ribbons, flat threads or splicing fibers made of foils or film strips and the individual threads also being able to have round or profiled, for example trilobal, cross sections. The titer of the individual threads can be, for example, 1 to 30 dtex, they are preferably 10 to 25 dtex. The number of individual threads in the thread bundles or yarns can be between 2 and a few thousand. The threads in the thread bundles can be partially stretched or total stretched out. It is also possible to use bundles of threads which have a certain pre-twist, for example up to 30 turns / m, in particular up to 25 turns / m, as a result of which they have better cohesion.

The thread bundles of linear or practically linear organic high molecular weight for the production of the thread are particularly customary linear synthetic high molecular weight polyamides with carbonamide groups recurring in the main chain, linear synthetic high molecular weight polyesters with recurring ester groups in the main chain, thread-forming olefin polymers, and cellulose derivatives such as cellulose derivatives. Suitable high-molecular compounds are in particular nylon-6, nylon-6.6, polyethylene terephthalate, linear polyethylene or isotactic polypropylene.

The gases used for this purpose are used as the flowing gaseous medium, for example nitrogen, carbon dioxide, water vapor and, in particular, from economical ones. Reasons, air. The required temperatures of the flowing medium can be within wide ranges. A temperature range of 80 to 550 ° C has generally been found to be expedient, the most favorable conditions for the respective material from the melting or plasticizing temperatures of these materials, the speed of the flowing medium at the respective temperature and the pressure used, the time during which the flowing medium acts on the thread bundles, the temperature at which the thread bundles are fed and also on the thickness of the individual threads, ie depend on the titer. Naturally one cannot use temperatures which lead to melting of the threads under the chosen conditions, although the temperatures themselves can be above the melting or decomposition points of the thread-forming materials used, provided that the threads run at a correspondingly high speed (short dwell time ) are led through the treatment zone. The higher the throughput speed, the higher the temperature of the medium can be above the plasticization range or the melting or decomposition point of the thread-forming material used.

The plasticizing range is, for example, for linear polyethylene at 80 to 90 ° C, for polypropylene at 80 to 120 ° C, for nylon-6 at 165 to 190 ° C, for nylon-6.6 at 120 to 240 ° C and for polyethylene terephthalate at 190 to 230 ° C.

The temperatures for the flowing medium are generally higher than the plasticizing temperatures; for nylon-6 e.g. When using air as the flowing medium, a temperature range of 175 to 380 ° C has been proven. For the other polymers, the lower limit of the preferred range is approximately 10 ° above the lower limit of the plasticization range and, depending on the residence time and titer, extends up to approximately 200 ° above the lower limit of the respective plasticization range.

The flowing medium is generally applied at a pressure of 2 to 15 bar, preferably 5 to 9 bar.

The texturing speed is 1200 to 3000 m / min. Speeds of 1800 to 2500 m / min are preferably used. High speeds result in shorter dwell times, which allow higher temperatures of the flowing medium.

The swirl sensor, which surrounds the tubular chamber (the thread guide tube), represents the narrowest point of the free cross section of the medium feed. It is advisable to dimension this free cross section at the narrowest point in such a way that throughputs of 0.35 to 2.0 m ³ (normal conditions) per hour and mm. Under these conditions, there are particularly high withdrawal tensions at the supply organs, for example the stretch godets. The amount of hot flowing medium to be used also depends on the yarn titer, the desired crimp intensity and the chemical nature of the thread bundle.

example 1

An undrawn polyamide 6 roving with the titer 4200 f 67 dtex is drawn off from a winding body and fed to the drawing device of a drawing texturing machine, with a drawing ratio of 1: 3.45 being set. The temperature of the inlet godet into the stretching field is 100 ° C and the temperature of the outlet godet of the stretching field is 150 ° C. The preheated and drawn thread is fed at a speed of 2000 m / min to a crimping device shown in FIG. Air of temperature 300 ° C. is supplied through the pipe socket 2 at a pressure of 5.3 bar. The air volume of 6.5 Nm ³ / h is now guided through the 8 air channels arranged in a circle, which are inclined counter-clockwise by 40 ° with respect to the axis of the texturing device. The free cross section of the annular space is 43 mm ² , the free area of the 8 air channels 14.4 mm ² ,

The yarn inlet nozzle 1 has a clear width of 1.1 mm. The thread guide channel 4 has a clear width of 2.4 mm, an outer diameter of 3.0 mm and a total length of 127 mm. This results in a ratio of the inside width of inlet nozzle 1 to the inside width of thread guide channel 4 of 1: 2.2. Between the inlet nozzle 1 and the thread guide channel 4 there is an annular gap 10 of 0.4 mm due to the set air flow. At the end of the thread guide channel 4 is the cylindrical slot nozzle, as in DE-B- 20 06 022 described, postponed. The distance between the end of the thread guide channel 4 and the beginning of the slots in the slot nozzle 5 is 0.83 times the outer diameter of the thread guide channel. The expansion zone consists of a slot nozzle 5 with 12 slots and a slot width of 0.5 mm. The tension of the thread to be textured is in front of the thread insertion channel. 65 cN. The yarn has a crimp of 12.6% (KWH).

Example 2

An undrawn polyamide 6 roving with the titer 4200 f 67 dtex is drawn off from a winding body and fed to the drawing device of a drawing texturing machine, with a drawing ratio of 1: 3.45 being set. The temperature of the inlet godet into the stretching field is 100 ° C and the temperature of the outlet godet of the stretching field is 150 ° C. The preheated and drawn thread is fed to a crimping device shown in FIG. 1 at a speed of 2000 m / min. Air with a temperature of 350 ° C. and a pressure of 5.3 bar is fed through the pipe socket 2. The air volume of 6.5 Nm ³ / h is now passed through the 8 air channels arranged in a circle, which are inclined counterclockwise by 15 ° with respect to the axis of the texturing device and leave 1/3 of the free cross-sectional area around the tubular chamber 4. The yarn inlet nozzle 1 has a clear width of 1.1 mm. The thread guide channel 4 has a clear width of 2.4 mm and an outer diameter of 3.0 and a total length of 127 mm. This results in a ratio of the inside width of inlet nozzle 1 to the inside width of thread guide channel 4 of 1: 2.2. Between the inlet nozzle 1 and the thread guide channel 4 there is an annular gap 10 of 0.4 mm due to the set air flow. At the end of the thread guide channel 4, the cylindrical slot nozzle, as described in DE-B-20 06 022, is pushed on. The distance between the end of the thread guide channel 4 and the beginning of the slots in the slot nozzle 5 is 0.83 times the outer diameter of the thread guide channel. The expansion zone consists of a slot nozzle 5 with 12 slots and a slot width of 0.5 mm. The tension of the thread to be textured is 45 cN in front of the thread insertion channel. The yarn has a crimp of 11.4% (KWH).

Example 3

In comparison to Example 1, an undrawn polyamide 6 roving with the titer 4200 f 67 dtex is drawn off from a winding body and fed to the drawing device of a drawing texturing machine, with a drawing ratio of 1: 3.45 being set. The temperature of the inlet godet in the stretching field is 100 ° C and the temperature of the outlet godet in the stretching field is 150 ° C. The preheated and drawn yarn is fed at a speed of 2000 m / min to a crimping device which corresponds to that used in Examples 1 and 2, but does not contain a twister 3. Air at a temperature of 390 ° C. is supplied through the pipe socket at a pressure of 5.3 bar. The air volume of 4.7 Nm / h is led directly through the air gap between the yarn inlet nozzle 1 and the thread guide channel 4. The air flow before entering the air gap runs parallel to the thread guide channel, i.e. without specific swirl.

The yarn inlet nozzle 1 has a clear width of 1.1 mm. The thread guide channel 4 has a clear width of 2.4 mm, an outer diameter of 3.0 mm and a total length of 127 mm. This results in a ratio of the inside width of inlet nozzle 1 to the inside width of thread guide channel 4 of 1: 2.2. Between the inlet nozzle 1 and the thread guide channel 4 there is an annular gap 10 of 0.3 mm due to the set air flow. At the end of the thread guide channel 4, the cylindrical slot nozzle, as described in DE-B-20 06 022, is pushed on. The distance between the end of the thread guide channel 4 and the beginning of the slots in the slot nozzle 5 is 0.83 times the outer diameter of the thread guide channel. The expansion zone consists of a slot nozzle 5 with 12 slots and a slot width of 0.5 mm. The tension of the thread to be textured is 30 cN before the thread insertion channel. The yarn has a crimp of 10.5% (KWH).

If the air is fed to the pipe socket 2 at a temperature of only 300 ° C., the yarn has a crimp of 8.2% (KWH).

Claims (4)

1. Process for texturizing bundles of filaments of synthetic high molecular weight materials at high speed, wherein the filament bundle (8) is passed through a feed nozzle (1) and is then brought into contact with a hot gaseous medium (9) which is undergoing a vortical motion, is heated by the fluid medium in a downstream tubular chamber (4) and then fed to an expansion stage (5) to produce the crimp, wherein the hot fluid medium (9) which is undergoing a vortical motion acquires a vortex angle of from 10 to 70°, preferably of from 20 to 50°, as a result of passing through a vortex inducer (3), the vortex angle being defined as the angle between the tangent to a helix and a line, parallel to the central axis of the system, which intersects the tangent.

2. A process as claimed in claim 1, wherein the fluid medium (9) at the free cross-section of the narrowest point of the vortex inducer (3) has, in the pressure range of from 2 to 15 bar and at a texturising speed of from 1,500 to 3,000 m/min, preferably from 1,800 to 2,500 m/min., a throughput rate of from 0.35 to 2.0 m³ (S.T.P.)/h per mm², preferably of from 0.4 to 1.0 m³ (S.T.P.)/h per m_m ².

3. An apparatus for texturizing bundles of filaments of synthetic high molecular weight materials, comprising a feed nozzle (1) for the filament bundle (8), one or more feeds (2) for a hot fluid medium to the filament bundle, the feeds being so constructed that they impart a vortical motion to the fluid medium, a downstream tubular chamber (4), in which the filament bundle is heated by means of the hot fluid medium, and an expansion stage (5), wherein one or more vortex inducers (3) are arranged in the feed(s) for the hot fluid medium (9) that have feeds that are constructed in such a way that the hot fluid medium (9) acquires a vortex angle of from 10 to 70°, especially a vortex angle of from 20 to 50°, the vortex angle being defined as the angle between the tangent to a helix and a line, parallel to the central axis of the system, which intersects the tangent.

4. An apparatus as claimed in claim 3 wherein the vortex inducer (3) is arranged in the immediate vicinity of the point at which the hot fluid medium (9) and the filament bundle (8) meet.

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