EP0635591B1 - Multifilament yarn with tendency to open out and good coherency, method for the production of multifilament yarn and its use - Google Patents

Description

The present invention relates to a multifilament flat yarn with good thread closure, a process for the production of multifilament flat yarns and their use, in particular in the form of thread chains which can be woven without sizing.

When used as a warp thread in a weaving machine, a yarn is subject to a large number of mechanical stresses. This includes influences of the dynamic stretching of the yarn, which can lead to loosening of the sizing film, partial dissolving of the intermingling and chafing of adjacent warp threads. Furthermore, the gradual passage through the warp thread monitor causes the yarns to rub against the slats; the constant change of subject causes a relative movement between adjacent filaments, which results in chafing and stretching of the filaments; the strands are subjected to multiple stresses, such as chafing or kinking; there is a scouring and a high relative movement in the reed. In addition, the yarns are damaged by functional elements of the loom, for example by relay nozzles, which can destroy the thread closure by piercing the yarn, and can cause filament breaks, which can lead to thread breaks.

In order to make the warp threads more resistant to mechanical stress during weaving and at the same time sticking protruding fibers or elementary threads to the thread, threads are sized. The sizing of warp chains from the processing of staple fiber yarns from natural fibers has long been known (see, for example, Falkai et al. "Synthesefaser", pp. 334-5, Verlag Chemie, 1981). The sizing is supposed to Combine the filaments of the yarn for the weaving process, but leave the yarns well separated from each other to form the shed.

This controversial requirement also persisted with yarns made of synthetic fibers and also with multifilament yarns. It is known that in multifilament yarns, sizing can be dispensed with by twisting which is sufficiently high for thread closure. However, twisting the yarn up is a complex and particularly cost-intensive process and also changes the appearance, feel and case of the textile surface made from such yarns.

From US-A-2,985,995 a compact interlaced yarn is described which has practically no twist and can be treated in textile processing processes without additional adhesives, such as sizing. Although according to the description, such further processing processes are also to be understood as weaving, such yarns, in particular smooth multifilament yarns, have so far not been able to establish themselves on the market as plain-free warp yarns. One of the reasons is to be seen in the fact that such yarns often break under the stresses that arise on the weaving machines, so that continuous operation over a longer period of time is not possible.

Further reasons can be found in the fact that the trouble-free processing of such yarns does not meet the requirements of modern, fast-running weaving machine systems in which the weft insertion, e.g. based on air or water, with more than 300 T / min up to 1200 T / min or even higher and / or can only be made in uncritical bindings with insufficient thread density in warp and weft.

DE-A-2,008,338 discloses blast-textured yarn which, according to the statements given there, can be used as a warp yarn in weaving without the use of a size. Yarns of this type can be woven directly into rifle looms without size or they can also be woven in as warp yarns Use water jet looms. Modern air looms and also water looms which have since been further developed differ from the looms mentioned in DE-A-2,008,338 in that they have a considerably higher weft insertion and shed change frequency. The yarns known from DE-A-2,008,338 are characterized by a so-called "entanglement resistance". The yarn describes this size by means of a static load test. It has now been found that the behavior of a yarn during the weaving process, in addition to good thread closure, is largely dependent on the tendency of the thread to open under dynamic mechanical stress. For this purpose - as defined below - the size of the opening tendency VS (K _F ) is an essential quality criterion. With the yarns claimed in the present patent application, it becomes possible to provide thread chains made from size-free smooth yarns which can be used without problems in weaving machines with shed changing and weft insertion frequencies of> 200 / min, in particular in air-jet weaving machines. It has now been found that the behavior of a yarn during the weaving process depends essentially on the tendency of the thread to open under dynamic mechanical stress and on good thread closure.

If previously known yarns are to be used, for example, as size-free warp yarns under the conditions prevailing in today's modern weaving machines, then failure generally occurs; especially when it comes to smooth multifilament yarns. These yarns either fluff and subsequently tear, or they tear immediately, or the loom can be insufficiently or not at all made to work by fluff-related shutdowns or, at best, with an inefficient efficiency of less than 80%, so that continuous operation over a longer period of time is hardly possible.

For example, EP-B-332,980 takes the view that a smooth filament yarn can now only be successfully sized with the highest tack and abrasion resistance.

From EP-A-323,986 a method for pre-intermingling a partially drawn polyester POY original yarn is known, in which the original yarn is interlaced at a certain air pressure. Attention is drawn to the good thread closure of the products obtained. This document only gives indications that this yarn ensures problem-free bobbin winding during further processing. There are no explanations as to whether the yarn produced can withstand the special stresses of the weaving process without the application of a size.

From JP-A-58-70,724 an unsized and untwisted polyester multifilament yarn is known that is suitable as a warp yarn for the production of fabrics. The yarn is characterized by a tensile strength of at most up to 2 g / denier.

Furthermore, from DE-A-3,903,970 a drawing and intermingling process for the production of flat polyester yarn is known, in which the yarn has to be spread out into a ribbon. There is no indication in this document to use such yarns as a warp, and certainly not as a sizing-free warp.

The advantages of yarns that can be woven without twisting or without the use of sizes are both economic and ecological. On the one hand, the sizing process is a further process step in the manufacture of fabrics and accordingly causes costs. On the other hand, sizes are usually removed from the fabric after the weaving process, which results in additional costs, waste materials and environmental pollution.

There is a need for yarns that can be woven without the use of sizes or high turns.

Experiments have shown that simply increasing the degree of intermingling of yarns - in analogy to twisting - did not achieve the desired success.

The degree of intermingling has so far been determined for the characterization of intermingled yarns. This is done with the help of known vortex testers.

Examples of this are needle test devices, mechanical thick / thin point scanners or optical thick / thin point sensors.

As a measure of the turbulence, the needle test value was usually given, measured with the Rothschild needle test device R 2040 or the HOOK-DROP test, as described in US Pat. No. 2,985,995; or the number of swirl nodes per unit length was measured, e.g. with the Reutlinger Interlace Counter or the "ITEMAT" from Enka Tecnica. Both measurement values assess the thread closure of the filaments in the yarn. With the help of these methods one obtains a statement about the length and number of the thread segments closed or left open by the intermingling.

However, these methods do not allow a statement to be made about the opening behavior of the intermingled yarn under dynamic mechanical stress, in particular about how such a yarn will behave when used as a warp thread on a weaving machine.

Attempts to determine the opening behavior of yarns have already been carried out. This includes placing pre-stretching devices in front of devices for determining the thread closure, for example placing such devices in front of the Reutlingen interlace counter (cf. Chemiefaser / Textilindustrie, 29 (10), pp. 862-4 (1979). This gives the option to define and uniaxially pre-stretch the thread to be tested, but this is a static load on the thread that does not apply to all applications, for example the behavior of the thread on a thread Weaving machine, can characterize sufficiently.

With the present invention, a multifilament smooth yarn is provided, which can be plainly woven even under the requirements of modern, fast-running weaving machine systems.

und das einen guten Fadenschluß aufweist, ausgedrückt durch die Größe $${\text{(VG}}_{\text{mittel}}{\text{/VG}}_{\text{max}}\text{) ∗ 100 \% > 45 \%, insbesondere > 50 \%}$$

wobei die Größen VG Verwirbelungsgrade darstellen, ermittelt mit dem Rothschild Nadeltestgerät Type 2040, VG_mittel den mittleren Nadeltestwert als arithmetisches Mittel von 20 Meßwerten darstellt und VG_max den maximalen Nadeltestwert als größten Wert von 20 Meßwerten darstellt, und wobei VS(K_F) die Verwirbelungsstabilität bei einer vorgegebenen Gesamtfadenspannung K_F darstellt, die durch Messung der Öffnungsneigung des Multifilamentglattgarns bei dynamisch-mechanischer Beanspruchung nach folgendem Verfahren ermittelt wird:

• a) Bestimmung des Verwirbelungsgrades VG_anf des zu prüfenden Multifilamentglattgarns mit dem Rothschild Nadeltester R 2040,
• b) Vorlage des Multifilamentglattgarns in einer Prüfstrecke definierter Länge, in welcher der Garnweg eine Ablenkung erfährt, welche Prüfstrecke zu Beginn und Ende von Transportvorrichtungen für das Garn sowie von einer zwischen den Transportvorrichtungen angeordneten Radialkraftmeßvorrichtung gebildet wird, wobei der Winkel zwischen den beiden Teilen des Garnweges etwa 50° bis etwa 5° beträgt, und wobei die Ablenkung durch die Anordnung der Transportvorrichtungen und der Radialkraftmeßvorrichtung hervorgerufen wird und Bewegen des Multifilamentglattgarns durch die Prüfstrecke unter einer vorgegebenen statischen Fadenzugkraft,
• c) periodisches Auslenken mit einer Frequenz, die der Fachwechsel-frequenz einer Webmaschine entspricht, insbesondere 8 bis 35 Hertz beträgt, des sich durch die Prüfstrecke bewegenden Multifilamentglatt-garns senkrecht zur Garnachse um eine vorbestimmte Länge mittels einer Auslenkvorrichtung, welche innerhalb der Prüfstrecke auf das zu prüfende Multifilamentglattgarn in einer solchen Weise wirkt, so daß bei der maximalen Auslenkung in dem Multifilamentglattgarn eine Gesamtfadenspannung K_F von 0,1 bis 1,0 cN/dtex resultiert, die sich aus einem Anteil der statischen Fadenzugkraft und einem Anteil der periodisch auf das Garn einwirkenden und durch das Auslenken hervorgerufenen dynamischen Fadenzugkraft zusammensetzt,
• d) Bestimmung der auf das Multifilamentglattgarn während seines Durchlaufs durch die Prüfstrecke einwirkenden Fadenzugkraft K_F mittels der Radialkraftmeßvorrichtung, wobei als K_F die Kraft angenommen wird, die zwischen zwei Auslenkungen des Multifilamentglattgarns durch die Auslenkvorrichtung auf dieses einwirkt,
• e) Bestimmung des Verwirbelungsgrades VG_ende des in der Prüfstrecke behandelten Garns mit dem Rothschild Nadeltester R 2040, und
• f) Ermittlung der Verwirbelungsstabilität VS bei einer vorgegebenen Gesamtfadenspannung K_F gemäß der Beziehung $${\text{VS(K}}_{\text{F}}{\text{) = (VG}}_{\text{anf}}{\text{/VG}}_{\text{ende}}\text{) ∗ 100 (\%).}$$
  

The invention relates to a multifilament flat yarn which has a slight tendency to open of the interconnected filaments, expressed in terms of size $${\text{VS (K}}_{\text{F}}\text{)> 42\%,}$$

and that has a good thread closure, expressed by the size $${\text{(VG}}_{\text{medium}}{\text{/ VG}}_{\text{Max}}\text{) ∗ 100\%> 45\%, especially> 50\%}$$

where the variables VG represent swirl degrees, determined with the Rothschild needle tester Type 2040, VG _{medium represents} the mean needle test value as the arithmetic mean of 20 measured values and VG _{max represents} the maximum needle test value as the largest value of 20 measured values, and where VS (K _F ) the swirl stability at a given total thread tension K _F , which is determined by measuring the tendency of multifilament smooth yarn to open under dynamic mechanical stress using the following method:

• a) determination of the _degree of intermingling VG of the _{multifilament plain} yarn to be tested with the Rothschild needle tester R 2040,
• b) Presentation of the multifilament smooth yarn in a test section of a defined length, in which the yarn path undergoes a deflection, which test section is arranged at the beginning and end of transport devices for the yarn and one arranged between the transport devices Radial force measuring device is formed, wherein the angle between the two parts of the yarn path is about 50 ° to about 5 °, and wherein the deflection is caused by the arrangement of the transport devices and the radial force measuring device and moving the multifilament smooth yarn through the test section under a predetermined static thread tension,
• c) periodic deflection with a frequency that corresponds to the change of shed frequency of a weaving machine, in particular 8 to 35 Hertz, of the multifilament smooth yarn moving through the test section perpendicular to the yarn axis by a predetermined length by means of a deflection device which within the test section points to the The multifilament smooth yarn to be tested acts in such a way that the maximum deflection in the multifilament smooth yarn results in a total thread tension K _F of 0.1 to 1.0 cN / dtex, which results from a portion of the static thread tension and a portion of the periodically on the Dynamic thread tension acting on the yarn and caused by the deflection,
• d) determination of the thread tensile force K _F acting on the multifilament flat yarn during its passage through the test section by means of the radial force measuring device, the force being assumed as K _F acting on the flat yarn between two deflections of the multifilament flat yarn by the deflection device,
• e) Determination of the degree of intermingling VG _end of the yarn treated in the test section with the Rothschild needle tester R 2040, and
• f) Determination of the intermingling stability VS for a given total thread tension K _F according to the relationship $${\text{VS (K}}_{\text{F}}{\text{) = (VG}}_{\text{beginning}}{\text{/ VG}}_{\text{The End}}\text{) ∗ 100 (\%).}$$
  

In the context of this invention, the term “multifilament smooth yarn” is understood to mean a multifilament yarn that is composed of a large number of individual filaments and that is not a high-twisted yarn. In general, that indicates yarn according to the invention practically no twist; however, it is possible that the yarn according to the invention has a protective twist, for example a twist of up to 50 T / m.

Practically all multifilament smooth yarns are suitable, which are made of continuous filaments and have been stabilized during their manufacture or further processing. These include, for example, nitrided, welded, glued, fused or, in particular, intermingled smooth yarns.

Examples of this are single or multi-component smooth filament yarns which have been subjected to stabilization, such as intermingling, preferably air intermingling.

With regard to the yarn-forming materials, the yarns according to the invention are not subject to any restrictions if yarns from filaments (continuous filaments) can be produced therefrom. It can be yarns made from semi-synthetic fibers, for example yarns made from cellulose fibers, or in particular yarns made from synthetic fibers, e.g. made from polyamides, polyolefins, polyacrylonitrile or in particular polyesters, such as polyethylene terephthalate or polybutylene terephthalate.

Filament yarns made of synthetic fibers, in particular polyester, which are very particularly preferably air-entangled, are particularly preferred.

The yarns can also be in the form of filament blends and / or plies.

Smooth yarns made from drawn multifilaments are very particularly preferred, in particular those with the dtex 76f128, 100f128, 76f64, 50f80 and 50f40 titers.

In the context of this invention, the term "plain weave" means a multifilament flat yarn which can be used practically when used as a thread chain in an otherwise customary weaving process and which does not require a size to carry out this weaving process. However, this does not mean that this yarn cannot have any of the customary preparations or finishing agents that have been applied to the yarn, for example to carry out or facilitate the manufacturing or further processing steps preceding the actual weaving process.

The present invention is made possible, inter alia, by the finding that, when used on the loom, sizes can be dispensed with if yarns with a certain tendency to open are used, and that simple control methods must be available for testing such yarns.

One such control method is the method described above for measuring the tendency of multifilament smooth yarn to open under dynamic mechanical stress. With the help of this method it is possible to sufficiently simulate the conditions prevailing on weaving machines and to develop yarns which correspond to the desired requirement profile.

The _degree of intermingling VG _beginning and _end VG of the yarn to be tested can be determined in a manner known _{per se} . Examples of turbulence testing devices are needle test devices or preferably mechanical thick / thin point scanners or in particular optical thick / thin point sensors.

Examples of mechanical thick / thin point scanners are the Reutlingen interlace counter, as described in chemical fibers / textile industry, 29 (10), pp. 862-4 (1979) or the Itemat test device for interlacing, as in chemical fibers / textile industry, 36/88 , Pp. 99 ff. (1986).

Examples of optical thick / thin point sensors are described in EP-A-465,842 and in EP-A-340,600; in the broadest sense, these are systems which, with the aid of optical methods, such as shading, diffraction or reflection, allow the measured variable to be assigned to the thick / thin areas of the tested yarn.

In the description of the yarn according to the invention given above, the determination of the degree of intermingling VG was specified with the aid of the Rothschild needle tester type 2040 for the purpose of definition. However, this does not mean that VG can only be determined with this device.

The term "degree of intermingling" is to be understood in the context of this description in the sense that it is a measured value which is obtained by testing the yarn according to the invention, that is to say also a non-intermingled yarn (for example a welded yarn) with a intermingling tester . With this measurement, the thread closure of the filaments in the yarn is assessed; ie length and number of closed or open thread segments.

With the control method described, the change in the thread closure or the change in the degree of intermingling of the yarn according to the invention is determined in a practical manner under a predetermined static thread tension and under an additional dynamic mechanical load.

To simulate the thread tension of the yarn in the test section, it undergoes a deflection in the section and is guided under a predetermined and non-pulsed tension. For this purpose, the yarn undergoes a deflection in the test section, the angle between the two parts of the yarn path being approximately 50 to approximately 5 °, and the deflection being caused by the arrangement of the transport devices and the radial force measuring device.

To simulate the thread tension of the yarn in the test section, it is transported between two transport devices under a predetermined static thread tension. The tension can be regulated in a manner known per se, for example by regulating the speed of the transport rollers.

During the test, the static thread tension is monitored by means of the thread tension measuring device.

The yarn is thus guided under a predetermined and non-pulsed tension in the test section.

The transport devices can be any device suitable for yarn transport. Examples of this are commercially available, motor-driven godets or delivery plants, preferably frequency-controlled.

The transport devices are preferably pairs of rollers around which the yarn to be tested is guided several times and the speed of which can be regulated separately. This makes it possible, for example, to simulate a tension as it occurs in a thread chain.

The thread tension measuring device can likewise be any device suitable for this purpose. Examples of this are the Rothschild tensiometer, the Honigmann Tensitron, the Denkendorf thread tension tensor or the thread tension meter from REES.

The length of the test track can fluctuate within wide limits; typical values are in the range from 50 to 3000 cm, preferably 150 to 200 cm (weaving machine dimensions).

To simulate the additional dynamic mechanical load on the yarn in the test section this experiences a periodic deflection in the test section perpendicular to the yarn axis by a predetermined length and at a predetermined frequency. This is done by means of a deflection device which acts on the yarn to be tested within the test section. The deflection device can be any device suitable for this purpose.

Examples of deflection devices are pistons or eccentrics operating perpendicular to the yarn axis and, in particular, blades rotating perpendicular to the yarn axis, which exert an impact pulse, defined in terms of height and frequency, on the moving yarn.

The frequency of the deflection device can also vary within wide limits; as well as the amount of tension impulses to be applied to the yarn. For the purposes of the present invention, frequency and tension pulses are selected in a range such that the behavior of a thread chain is simulated on a weaving machine.

Typical values for the frequency of the deflection device are in the range from 5 to 50 Hz, preferably in the range from 8 to 35 Hz.

Typical values for the magnitude of the tension impulses to be applied to the yarn lie in such a range that the total tension in the yarn - i.e. the sum of the static yarn tension and the proportion of the tension acting periodically on the yarn (values of the tension amplitude) - is in the range of 0 , 05 to 1.0 cN / dtex, preferably in the range from 0.1 to 0.7 cN / dtex.

The method described above for characterizing thread chains is very particularly preferably used. For this purpose, the yarn is passed through the test section in the form of a thread chain. The check is carried out either one after the other on individual skeins or on several Yarn strands of the thread chain or on all thread strands of the thread chain. Such thread chains preferably consist of two to five yarns; the deflection device preferably acts on a plurality of such yarns.

From the control method described, the degree of intermingling VG _beginning and _end VG are obtained as measured variables, for example as the number of intermingling points per unit length of the yarn.

A test variable is the tendency of the yarn according to the invention to open under the test conditions in the test section.

The evaluation of the measured variables VG _beginn and VG _end at a predetermined total _{thread tension} K _F can be carried out in different ways.

The quotients VG _beginn / VG _end or VG _end / VG _beginn at a certain total _{thread tension} K _F are a characteristic for the behavior of the yarn under dynamic mechanical loading.

ermittelt.For the purposes of describing preferred yarns according to the invention, a swirl stability VS (K _F ) at a certain total thread tension K _F and under a certain tension pulse of a given frequency according to the relationship is used as a measure of the tendency to open under dynamic mechanical loading of these yarns $${\text{VS (K}}_{\text{F}}{\text{) = (VG}}_{\text{beginning}}{\text{/ VG}}_{\text{The End}}\text{) ∗ 100 (\%)}$$

determined.

For the purposes of the present description, the total thread tension K _F is the sum of the static thread tension and a portion of the periodically acting on the yarn and caused by the deflection dynamic thread tension assumed in the deflected yarn as it is transported through the test section.

The distribution of the measured values of the degree of intermingling VG of yarns usually obeys a Poisson function. However, with the same mean values, this is dependent on different parameters, such as yarn material, the conditions during the creation of the thread closure and thread running conditions, and its width is very different.

With the control method described, it is possible to provide an additional and more meaningful quality criterion for the thread closure of the thread in addition to the mean values of the distribution of the degree of intermingling for a specific thread.

It was found that it is particularly problematic when used as a sizing-free warp yarn to operate with the mean values of the distribution of the degree of intermingling. It was also found that it is appropriate here to use the extreme values of a series of measurements instead of these mean values of the degree of intermingling, since these generally determine the running behavior of these yarns on a weaving machine.

It has been found that the running behavior of multifilament smooth yarns on a weaving machine requires good thread closure which, owing to the size defined above (VG _medium / VG _max ) ∗ 100%> 45%, preferably 50%, in particular> 67%, particularly preferably 55 to 67%, is characterized.

In a further preferred embodiment, in addition to the sizes VS (K _F ) and VG _medium / VG _max , the yarn according to the invention has values of VG _max <30 mm, preferably from 11 to 22 mm, in particular from 18 to 22 mm with the Rothschild needle tester type 2040.

wobei VG_mittel die oben definierte Bedeutung aufweist ermittelt über das Rothschild Nadeltestgerät Type 2040 und IL_mittel die mittlere Anzahl der Verwirbelungspunkte pro Fadenmeter ist, ermittelt mit dem Reutlinger Interlace Counter oder dem ITEMAT.In a further preferred embodiment, the inventive In addition to the above-mentioned sizes VS (K _F ) and VG _medium / VG _max, values of LK _medium <15 mm, preferably <6.0 mm, particularly preferably 1.6 to 5.6 mm, with LK _medium the medium length which means swirl points, determined according to the relationship $${\text{LK}}_{\text{medium}}{\text{= (1000 - (VG}}_{\text{medium}}{\text{∗ IL}}_{\text{medium}}{\text{)) / IL}}_{\text{medium}}\text{,}$$

where VG _{medium has} the meaning defined above, determined with the Rothschild needle tester Type 2040 and IL _{medium with} the mean number of intermingling points per thread meter, determined with the Reutlingen interlace counter or ITEMAT.

Preferred multifilament flat yarns according to the invention have VS (K _F ) values which are in the range from 60 to 100%.

Particularly preferred are multifilament flat yarns, as defined above, whose VS (K _F ) value is 45-90% and which is measured at a frequency of 15 Hertz and with such a maximum deflection in step c), so that at the maximum deflection in the multifilament smooth yarn results in a total thread tension K _F of 0.2 to 0.42 cN / dtex (measured with the Denkendorf thread tension tensor DEFAT).

The multifilament smooth yarns according to the invention are particularly preferably in a size-free manner and in the form of a thread chain. It is known per se that thread chains with high thread densities are particularly difficult to weave. It has been found that the yarn according to the invention can be woven without size in the form of thread chains with high thread densities. The invention therefore also relates to thread chains in which the thread densities are more than 20 threads / cm, in particular greater than or equal to 40 threads / cm.

The single-filament titer of the multifilament flat yarns according to the invention can fluctuate within wide limits; typically this titer is 0.3 to 6.5 dtex, preferably 0.6 to 1.5 dtex, and very particularly preferably less than 1.0 dtex.

The yarn titer of the multifilament smooth yarns according to the invention can also vary within wide limits; typically this yarn titer is 20 to 600 dtex, preferably 40 to 400 dtex. The number of filaments of the multifilament flat yarn according to the invention typically ranges from 20 to 250, preferably from 40 to 180.

Types with lower filaments are particularly difficult to use as warp yarns. It is therefore to be regarded as particularly surprising that such yarns can still be woven without difficulty without any problems.

The invention therefore preferably relates to multifilament flat yarns, as defined above, with capillary numbers from 20 to 80, in particular from 30 to 50.

The multifilament smooth yarns according to the invention are notable for high strength; in the case of plain polyester yarns, the tensile strengths are more than 2 g / denier, preferably more than 3 g / denier.

The multifilament smooth yarns according to the invention are usually fluid-interlaced multifilament yarns, preferably air-interlaced multifilament yarns.

The invention also relates to a production method for producing interwoven multifilament smooth yarns which can be woven without the need for sizing. It has been found that multifilament smooth yarns can be produced with sufficient thread closure and sufficient opening tendency for the plain weaving if the thread is guided with low tension at the location of the intermingling and is preferably carried out in the context of the low tension with particular tension constancy. The method according to the invention is characterized in that the yarn tension at the location of the intermingling has the value of May not exceed 0.6 cN / dtex.

• i) Vorlage mindestens eines ein- oder mehrkomponentigen Multifilamentvorgarns und Zuführen dieses Multifilamentvorgarns zu mindestens einer Verwirbelungsdüse,
• ii) Verwirbeln des Multifilamentvorgarns in der Verwirbelungsdüse mittels eines Fluids, vorzugsweise Luft unter einer solchen Voreilung des Multifilamentvorgarns und unter einem solchen Druck des Verwirbelungsfluids, daß sich ein im wesentlichen glattes, verwirbeltes Multifilamentgarn ausbildet, wobei gegebenenfalls vor und/oder nach dem Ort mindestens einer Verwirbelung eine Flüssigkeit auf das Garn appliziert wird, die keine Schlichte darstellt und
• iii) Abziehen des verwirbelten Multifilamentglattgarns aus der Verwirbelungsdüse, mit der Maßgabe, daß die Spannung des Garns so gewählt wird, so daß dieses am Ort der Verwirbelung unter einer Spannung von kleiner gleich 0,6 cN/dtex steht.

The invention therefore also relates to a process for the production of plain-weave and intermingled multifilament smooth yarns comprising the measures

• i) supplying at least one single-component or multi-component multifilament roving and feeding this multifilament roving to at least one intermingling nozzle,
• ii) intermingling the multifilament roving in the intermingling nozzle by means of a fluid, preferably air, under such an advance of the multifilament roving and under such a pressure of the intermingling fluid that an essentially smooth, intermingled multifilament yarn is formed, optionally before and / or after the location of at least one A fluid is applied to the yarn that is not a size and
• iii) pulling the interlaced multifilament smooth yarn out of the interlacing nozzle, with the proviso that the tension of the yarn is chosen so that it is under the interlacing at a tension of less than or equal to 0.6 cN / dtex.

The method according to the invention is particularly preferably carried out such that the yarn tension is kept particularly constant at the location of the intermingling, in particular that the fluctuation in the yarn tension is less than + / - 0.1 cN / dtex. This constant voltage can be achieved by means of measures known per se, for example in that supply mechanisms or godets are controlled and regulated by frequency converters.

Any one- or multi-component filament yarns can be used as master yarns; these yarns are usually drawn before interlacing, unless the filament yarns are the fastest spun and can no longer be drawn.

The rovings are usually fully drawn yarns, i.e. for types whose maximum tensile force elongation at 25 ° C is less than 80%.

The orientation and stretching of the spun threads can be carried out in a manner known per se. For example, a fully oriented yarn (FOY) can already be produced during the spinning process, which generally no longer needs to be drawn; or it is possible to produce a yarn which can be subsequently processed into a drawn yarn in a post-drawing process. These latter post-stretchable yarns are usually LOY, MOY, HOY or POY yarns. The terms LOY, MOY, HOY, POY and FOY are well known and e.g. in chemical fibers / textile industry, 6/1985, p. 411-2.

The stretching can follow the spinning process directly or can be carried out in a separate step, for example combined with a customary aftertreatment, such as fixing.

The stretching can also take place immediately before the feed to the swirling nozzle, for example by means of upstream stretching godets. This variant can be carried out within a post-treatment section or integrated in the spinning process before the location of the intermingling.

The stretching and swirling can take place in succession in one step, e.g. by swirling a FOY yarn directly in the spinning shaft before winding the yarn. However, it can also only take place in a downstream process, for example by rewinding or re-looping.

The stretching and swirling can also take place in two or more stages. For example, yarns in spinning can be partially oriented, for example as LOY, MOY, HOY or POY yarns, and can then be drawn in a subsequent stage, for example in drawing bobbins or drawing twists. This is done here Swirling only in a subsequent process step after the yarn has been drawn and before it is wound up.

In a preferred embodiment of the method according to the invention, the intermingling is integrated in a device for carrying out textile processes which is known per se and which has godet pairs which allow the yarn to be guided with low tension. Examples of this are texturing devices, twisting devices or rewinding devices. These devices can additionally be equipped with stretching devices, for example with pairs of godets moving at different speeds.

The invention preferably relates to a intermingling process, as defined above, wherein a yarn is used as the multifilament roving, the maximum tensile strength at 25 ° C of which is less than 80%, which is intermingled in a known device for carrying out textile processes, which has pairs of godets that allow low-tension guiding of the yarn and between which godet pairs there is at least one intermingling nozzle.

The invention preferably relates to a intermingling process, as defined above, wherein a yarn is used as multifilament roving, the maximum tensile elongation at 25 ° C is more than 80%, which is subjected to stretching immediately before the intermingling, so that its maximum tensile elongation at 25 ° C after the drawing is less than 80%, and which is subsequently swirled, the drawing device and at least one swirling nozzle being integrated in a device for carrying out textile processes which is known per se and which has godet pairs which allow the yarn to be guided with little tension and between which godet pairs there are at least one swirl nozzle is located.

In the process according to the invention, preference is given to using a FOY yarn, in particular a FOY yarn, which after the Spinning is fed directly to the intermingling, tension isolation being carried out between the spinning process and the intermingling. This is preferably done by means of pairs of rollers around which the yarn is guided without slippage before it enters the intermingling nozzle.

One- or multi-component yarns can be selected that run into the intermingling unit once or several times and in any case leave it as a compact yarn.

The intermingling can also be carried out in several stages, the yarn passing through a number of intermingling nozzles connected in series.

In the case of a plurality of swirling nozzles connected in series, these can either all be arranged in a voltage-insulated zone or the swirling nozzles are arranged in more than one voltage-insulated zone connected in series.

The presentation and feeding of the multifilament roving to the intermingling nozzle takes place by means of measures and devices which are conventional per se. When texturing yarns for the blowing nozzle, it is known that the filament material is fed to the blowing nozzle at a higher speed than is drawn off from it. The excess speed of the feed compared to the take-off, expressed as a percentage based on the take-off speed, is referred to as the advance. When presenting, make sure that the advance of the multifilament roving is selected so that a practically lint-free and loop-free yarn is formed. This is usually the case with leads of less than 3%. In individual cases, however, higher leads can be selected as long as a smooth, intermingled yarn is formed, preferably a multifilament smooth yarn which has the above-defined values for the opening tendency and the thread closure of the interconnected filaments.

The multifilament roving is intermingled in the intermingling nozzle by means of a fluid, for example by means of liquids or in particular by means of gases. Air is preferred. The intermingling pressure is to be selected in the individual case so that the required maximum limit of the yarn tension at the location of the intermingling is not exceeded and that a smooth yarn is formed. Typical values for the swirl pressure are 1.5 to 7.5 bar.

The roving is preferably swirled with air with the addition of a liquid which wets the roving during the swirling process, for example water.

Examples of swirling nozzles can be found in US Pat. No. 2,985,995, the disclosure of which is also the subject of the present description.

After intermingling, the multifilament flat yarn formed is drawn off from the intermingling nozzle. This can be done by means of devices known per se, for example with godets. When choosing the withdrawal tension, care should be taken that the tension of the yarn at the location of the intermingling is less than or equal to 0.6 cN / dtex, preferably 0.1 to 0.4 cN / dtex.

The intermingled multifilament smooth yarn can then be subjected to a fixing treatment by passing it through a heating device; typical temperatures of the yarn as it passes through the heating device are in the range from 60 to 250 ° C.

The method according to the invention can be carried out on individual, unground or folded yarns, which are then wound up and processed into a thread chain in a further step. However, the method can also be integrated into the production of warp beams by the swirling by means of a plurality of swirling nozzles connected in parallel on the one provided for the production of the warp beam Thread is carried out. Examples of such integrated methods can be found in DE-AS-2,611,547, EP-A-152,919, EP-A-216,951, DE-A-3,711,767, and DE-A-3,727,262.

In the embodiment of the method according to the invention with more than one swirling nozzle, for example with several swirling nozzles connected in series and / or in parallel, the conditions during swirling at each of these nozzles can be kept the same or different; in particular, the type of nozzles can be varied or process parameters such as thread tension, intermingling pressure or the application of liquid before and / or after the location of the intermingling on the yarn.

The multifilament smooth yarn according to the invention can preferably be used in applications in which a low tendency to open such yarns is a prerequisite.

Examples of such applications are the use of such yarns without the use of any sizes in the warp knitting and in particular in the weaving mill. The invention therefore also relates to the use of the yarns for these purposes.

The following examples illustrate the invention without limiting it.

Example 1: Production of a size-free plain yarn chain from FOY with the title dtex 50f40

FOY of the titer dtex 50f40 x 1 round made of polyethylene terephthalate is used as the original yarn. The yarn is spun using technology known per se, e.g. in DE-A-2,117,659.

A swirled yarn is produced from the original yarn thus produced by rewinding on a winding machine. When rewinding, the yarn is air-swirled at a frequency of 1100 knots / second. The thread tension when entering the swirl nozzle, it is kept particularly constant and is less than 0.6 cN / dtex. The winding tension is also less than 0.6 cN / dtex.

The finished yarn is characterized by the following characteristic data: Total thread tension K _F (cN / dtex) VS (K _F ) (%) VG _medium (mm) VG _max (mm) IL _medium (1 / m) LK _medium (mm) unencumbered 100 12th 18th 76 2.5 0.2 96 12th 18th 73 2.0 0.4 86 12th 22 65 1.6 0.6 57 21 65 43 1.3

K_F:

Gesamtfadenspannung ermittelt mit dem Denkendorfer Fadenspannungstensor (DEFAT)

VS(K_F)

Öffnungsneigung (wie oben definiert) ermittelt mit dem Rothschild Nadeltestgerät Type R 2040

VG_mittel

Mittlerer Nadeltestwert (arithmetisches Mittel von 20 Meßwerten) ermittelt mit dem Rothschild Nadeltestgerät Type R 2040

VG_max

Maximaler Nadeltestwert (größter Wert von 20 Meßwerten) ermittelt mit dem Rothschild Nadeltestgerät Type R 2040

IL_mittel

Mittlere Anzahl der Verwirbelungspunkte pro Fadenmeter ermittelt mit dem Reutlinger Interlace Counter

Lk_mittel

Mittlere Länge der Verwirbelungsknoten errechnet nach der Beziehung (1000 - (VG_mittel ∗ IL_mittel)) /IL_mittel

The measured variables in the table above were determined using the following methods:

K _F :

Total thread tension determined with the Denkendorfer thread tension tensor (DEFAT)

VS (K _F )

Opening tendency (as defined above) determined with the Rothschild needle tester type R 2040

VG _medium

Average needle test value (arithmetic mean of 20 measured values) determined with the Rothschild needle tester type R 2040

VG _max

Maximum needle test value (largest value of 20 measured values) determined with the Rothschild needle tester type R 2040

IL _medium

Average Rewlinger interlace counter determines the number of interlacing points per thread meter

Lk _medium

Average length of the intermingling nodes calculated according to the relationship (1000 - (VG _medium ∗ IL _medium )) / IL _medium

The finished yarn was warmed in 40 threads / cm on a warp beam. This thread chain could easily be processed on a RÜTI air weaving machine.

Example 2: Production of a size-free plain yarn chain from FOY with the title dtex 76f128

FOY of the dtex 76f128 x 1 titer made of polyethylene terephthalate is used as the original yarn. The yarn is spun using technology known per se, e.g. in DE-A-2,117,659.

The master yarn thus produced is air-swirled on-line before the first winding at a frequency of 5500 knots / second. The thread tension when entering the intermingling nozzle is kept particularly constant and is less than 0.6 cN / dtex. Following the swirling of air, the yarn is wound up. The winding tension is less than 0.6 cN / dtex.

The finished yarn is characterized by the following characteristic data:

K_F:

Gesamtfadenspannung ermittelt mit dem Denkendorfer Fadenspannungstensor (DEFAT)

VS(K_F)

Öffnungsneigung (wie oben definiert) ermittelt mit dem Rothschild Nadeltestgerät Type R 2040

VG_mittel

Mittlerer Nadeltestwert (arithmetisches Mittel von 40 Meßwerten) ermittelt mit dem Rothschild Nadeltestgerät Type R 2040

VG_max

Maximaler Nadeltestwert (größter Wert von 40 Meßwerten) ermittelt mit dem Rothschild Nadeltestgerät Type R 2040

IL_mittel

Mittlere Anzahl der Verwirbelungspunkte pro Fadenmeter ermittelt mit dem Reutlinger Interlace Counter

LK_mittel

Mittlere Länge der Verwirbelungsknoten errechnet nach der Beziehung (1000 - (VG_mittel ∗ IL_mittel)) / IL_mittel

The measured variables in the table above were determined using the following methods:

K _F :

Total thread tension determined with the Denkendorfer thread tension tensor (DEFAT)

VS (K _F )

Opening tendency (as defined above) determined with the Rothschild needle tester type R 2040

VG _medium

Average needle test value (arithmetic mean of 40 measured values) determined with the Rothschild needle tester type R 2040

VG _max

Maximum needle test value (largest value of 40 measured values) determined with the Rothschild needle tester type R 2040

IL _medium

Average Rewlinger interlace counter determines the number of interlacing points per thread meter

LK _medium

Average length of the intermingling nodes calculated according to the relationship (1000 - (VG _medium ∗ IL _medium )) / IL _medium

The finished yarn was warmed in 40 threads / cm on a warp beam. This thread chain could easily be processed on a RÜTI air weaving machine.

Example 3: Adjustment of a yarn known from DE-A-2,008,338 and checking the running behavior of this yarn for different, fast running looms

Example 1 of DE-A-2,008,338 lists the following yarn by name and by way of example:

Yarn of polyethylene terephthalate threads of denier 70 den f 34; this yarn is swirled at 2697 m / min under a thread tension of 17 g at pressures of at least 4.6 atm in type A nozzle device described in more detail there. It is a commercially available nozzle device with the designation "Roto Set nozzle"

This yarn is processed according to DE-A-2,008,338 on a shuttle loom as follows:

Weaving at 192 strokes per minute on a "Draper-XD shooter loom" with 129 warp threads / 2.54 cm and 46 weft threads / 2.54 cm; a commercially available blended yarn made of polyester staple fibers and cotton of the type Nm 26/1 is used as the weft yarn; the efficiency is 90%. There is no further information about the fabric construction

For comparison with the property profile of the yarns described and claimed in the present patent application, this previously known yarn was reproduced, approximately using a yarn made from polyethylene terephthalate threads of 76 dtex f 32. The process and the "interlocking nozzle device" according to DE-A-2,008,338 were used.

An attempt was made to obtain the yarn obtained without size and in a comparable manner, but with a change of subject or. Weave weft insertion frequencies of more than 200 / min on air and water and rapier weaving machines.

Before interweaving, that obtained in accordance with DE-A-2,008,338 swirled yarn examined for its specifications in terms of thread closure and opening tendency. It was tested according to the manner described in the present patent application. The following key data for thread closure and opening tendency were determined: K _F (cN / dtex) VS (K _f ) (%) VG _medium (mm) VG _max (mm) IL _medium (1 / m) LK _medium (mm) 0.00 100 48 89 20th 1.8 0.20 40 122 326 8th 1.2 0.40 35 138 430 5 0.6 0.60 13 368 1795 2nd 0.4

It should therefore be noted that the yarn reproduced according to DE-A-2,008,338 does not meet the specifications given in the claims of the present patent application.

It was not even possible to begin weaving this re-enacted yarn on air and water looms. A certain success could be achieved on rapier weaving machines with a non-critical twill and atlas weave up to a frequency of 300 / min.

The efficiency (ratio of the time practically required under the given machine settings at full capacity to the time theoretically required) was less than 90%, however, below the standard that is common today.

Plain-weave fabrics in the density mentioned in DE-A-2,008,338, however, could not be produced either.

Claims (30)

1. A flat multifilament yarn with low opening tendency for the mutually cohered filaments, expressed by the quantity $${\text{VS(K}}_{\text{F}}\text{) > 42\%}$$

   

   and with good cohesion, expressed by the quantity $${\text{(VG}}_{\text{mean}}{\text{/VG}}_{\text{max}}\text{) * 100\% > 45\%,}$$

   

   where the VG quantities are degrees of intermingling determined using the Rothschild needle tester model 2040, VG_mean being the arithmetic mean of 20 needle test measurements, and VG_max being the maximum value of 20 needle test measurements, and where VS(K_F) is the intermingling stability at a given total yarn tension K_F determined by measuring the opening tendency of the flat multifilament yarn under dynamic-mechanical stress by the following method:

   a) determining the degree of intermingling VG_init of the flat multifilament yarn to be tested using the Rothschild needle tester R 2040,

   b) feeding the flat multifilament yarn into a testing zone of defined length in which the yarn path undergoes a deflection and which is formed at the beginning and end of transport devices for the yarn and of a radial force measuring device, disposed between the transport devices, the angle between the two parts of the yarn path being about 50° to about 5°, and the deflection being caused by the arrangement of the transport devices and of the radial force measuring device, and movement of the flat multifilament yarn through the testing zone under a given static yarn-pulling force,

   c) periodically deflecting the flat multifilament yarn moving through the testing zone at a frequency which corresponds to the change of shed frequency of a weaving machine, in particular 8 to 35 hertz, perpendicularly to the yarn axis by a predetermined length by means of a deflecting device which acts within the testing zone on the flat multifilament yarn to be tested in such a way that maximum deflection produces within the flat multifilament yarn a total yarn tension K_F from 0.1 to 1.0 cN/dtex which is composed of a proportion of the static yarn-pulling force and a proportion of the dynamic yarn-pulling force acting periodically on the yarn and caused by the deflecting,

   d) determining the yarn-pulling force K_F acting on the flat multifilament yarn during its passage through the testing zone by means of the radial force measuring device, K_F being taken as the force which acts on the flat multifilament yarn between two deflections of the flat multifilament yarn due to the deflecting device,

   e) determining the degree of intermingling VG_end of the yarn treated in the testing zone using the Rothschild needle tester R 2040, and

   f) determining the intermingling stability VS at a given total yarn tension K_F according to the relation $${\text{VS(K}}_{\text{F}}{\text{) = (VG}}_{\text{init}}{\text{/VG}}_{\text{end}}\text{) * 100 (\%).}$$

   
2. The flat multifilament yarn of claim 1 with its good cohesion expressed by $${\text{(VG}}_{\text{mean}}{\text{/VG}}_{\text{max}}\text{) * 100\% > 45\%, especially > 67\%.}$$

   
3. The flat multifilament yarn of claim 1 with its good cohesion additionally expressed by $${\text{VG}}_{\text{max}}\text{< 30 mm, especially from 11 to 22 mm,}$$

   

   where VG_max is determined by the method defined in claim 1.
4. The flat multifilament yarn of claim 1 with its good cohesion additionally expressed by the relation $${\text{LK}}_{\text{mean}}\text{< 15 mm, preferably 6.0 mm, particularly preferably 1.6 to 5.6 mm,}$$

   

   where LK_mean is the mean length of the intermingling nodes determined according to the relation $${\text{LK}}_{\text{mean}}{\text{= (1000 - (VG}}_{\text{mean}}{\text{* IL}}_{\text{mean}}{\text{))/IL}}_{\text{mean}}$$

   

   where VG_mean has the meaning defined in claim 1 and is determined via the Rothschild needle tester model 2040, and IL_mean is the mean number of intermingling nodes per yarn meter determined using a Reutlingen Interlace Counter or an ITEMAT.
5. The flat multifilament yarn of claim 1 where VS(K_F) is 45-90% measured at a frequency of 15 hertz and at such a maximum deflection in step c) that maximum deflection produces within the flat multifilament yarn a total yarn tension from 0.2 to 0.42 cN/dtex (measured using the Denkendorf yarn tension tensor).
6. The flat multifilament yarn of claim 5 where (VG_mean/VG_max) * 100% is 55 to 67%.
7. The flat multifilament yarn of claim 5 where VG_max is 18 to 22 mm.
8. The flat multifilament yarn of claim 5 where LK_mean is 1.6 to 2.0 mm, LK_mean being defined as in claim 4.
9. The flat multifilament yarn of claim 1 where VS(K_F) is 60 to 100%.
10. The flat multifilament yarn of claim 1 where the cohesion is achieved by air intermingling.
11. The flat multifilament yarn of claim 1 comprising polyester, especially polyethylene terephthalate.
12. The flat multifilament yarn of claim 11 having breaking strengths of more than 3 g/denier.
13. The flat multifilament yarn of claim 1 without a size and in the form of a warp.
14. The flat multifilament yarn of claim 13 where the thread count in the warp is more than 20 threads/cm.
15. The flat multifilament yarn of claim 1 wherein the number of filaments is more than 20.
16. A process for producing an intermingled flat multifilament yarn as claimed in claim 1 which is weavable without a size, comprising the measures of

    i) presenting at least one one- or multi-component multifilament feed yarn and feeding this multifilament feed yarn to at least one intermingling jet,

    ii) intermingling the multifilament feed yarn in the intermingling jet by means of a fluid, preferably air, under such an overfeed of the multifilament feed yarn and under such a pressure of the intermingling fluid as to form an essentially flat, intermingled multifilament yarn, and

    iii) withdrawing the intermingled flat multifilament yarn from the intermingling jet, with the proviso that the tension on the yarn is chosen in such a way that it is under a tension of not greater than 0.6 cN/dtex at the site of intermingling.
17. The process of claim 16 wherein the fluctuation in the yarn tension is less than +/- 0.1 cN/dtex at the site of intermingling.
18. The process of claim 16 wherein the multifilament feed yarn used is a yarn whose ultimate tensile strength extension at 25°C is less than 80% which is intermingled in a conventional apparatus for carrying out textile processes which has godet pairs which permit a low-tension guiding of the yarn and between which godet pairs there is situated the intermingling unit.
19. The process of claim 16 wherein the multifilament feed yarn used is a yarn whose ultimate tensile strength extension at 25°C is more than 80% which is subjected, directly prior to the intermingling, to a drawing so that its ultimate tensile strength extension at 25°C after drawing is less than 80% and which is subsequently intermingled, the drawing means and the intermingling unit being integrated in a conventional apparatus for carrying out textile processes which has godet pairs which permit a low-tension guiding of the yarn and between which godet pairs there is situated the intermingling unit.
20. The process of claim 16 wherein there is used an FOY yarn which within a single-stage process is directly after the spinning carried off to the intermingling, a tension isolation being effected between spinning process and intermingling.
21. The process of claim 16 wherein the overfeed of the multifilament feed yarn is less than 3%.
22. The process of claim 16 wherein the feed yarn is intermingled with air in the presence of a liquid which wets the feed yarn during the intermingling process.
23. The process of claim 16 wherein the tension on the yarn at the site of intermingling is from 0.1 to 0.5 cN/dtex.
24. The process of claim 16 wherein the flat multifilament yarn is subjected to a setting treatment following intermingling.
25. The process of claim 16 wherein the intermingling is carried out by means of a multiplicity of parallel-guided intermingling jets on the yarn sheet envisaged for producing the warp beam.
26. The process of claim 16 wherein the intermingling is carried out with more than one intermingling jet connected in series.
27. The process of claim 26 wherein the intermingling jets connected in series are all disposed in a tension-isolated zone.
28. The process of claim 26 wherein the intermingling jets are disposed in more than one tension-isolated zone connected in series.
29. The use of flat multifilament yarns of claim 1 in knitting and weaving without the use of sizes.
30. A use as claimed in claim 29, wherein the yarns are used as warp yarns for producing woven fabrics.