EP0022065B1 - False-twist-draw-textured multifilament yarn made of synthetic polymers, and process for its production - Google Patents

Description

The invention relates to a false twist textured filament yarn made of synthetic polymers, consisting of a filament group forming a core and a filament group lying on the outside of the core and partially enveloping the core, the two filament groups being produced from the same or different polymers. The invention further relates to a method for producing the above-mentioned filament yarn.

In recent years there has been increasing interest in synthetic filament yarns that are similar to natural fiber yarns. The better this resemblance to natural fiber yarns, the better the so-called "spun-like effect". In recent years, core wrapping threads have become more important because such threads can achieve a relatively good spun-like effect. For example, DE-OS 22 55 460 relates to a process for the production of synthetic, false twist textured, endless core yarns which consist of at least one core component and a sheathing component which differ in their stretchability under tension, both polyamide and polyester being used. Different extensibility can be obtained by using different polymer starting materials or different winding speeds during spinning. According to this method core yarns can with a good spunlike _- effect can be produced, but if you want to process these core yarns, for example, on a knitting machine, big problems caused by frequent Maschinenabsteller. The presence of protruding fibrils in the wrapping thread causes a great restraining force when knitting, which must be overcome in order to continue the knitting process. Since large restraint forces lead to errors in the knitted goods produced, shut-off devices are attached to the knitting machines, which shut down the machine when large restraint forces occur. A large number of shutdowns, as they occur with these core yarns, are not economically viable for the processor.

On the other hand, DE-OS 19 15821 describes a core yarn in which the enveloping filaments have the same or a coarser titer than the core filaments. According to Examples 1 and 3 of this patent, the core component consists of 84 den / 10 threads or 96 den / 10 threads and the covering component consists of 75 den / 2 threads or 96 den / 2 threads. DE-GM 77 34 062 describes a voluminous, false-twist textured filament yarn made of polyester, which consists of a core with between 12 and 100 fibrils and a covering with between 1 and 10 fibrils, the fibrils of the core group having a smaller titer than the fibrils of the Have wrapping group. The yarns according to the above-mentioned DE-OS 1915821 and GM 77 34 062 have a crepe-like effect and no spun-like effect, but instead a fairly good process, i. H. a small restraint when knitting, which leads to almost no machine shutdowns when knitting.

The invention has for its object to provide a false twist textured filament yarn, consisting of a filament group forming a core and a filament group enveloping the core, in which the above-mentioned disadvantages can be avoided. It is therefore important to produce a filament yarn that has a good spun-like effect and a good process for processing, for example on knitting machines.

According to the invention, this object is achieved in that the sheathing filament group consists of at least two filament groups of different fibril titers, the smaller portion of the sheathing filament group comprising the fibrils with the coarsest fibril titer and the larger portion of the sheathing filament group comprising the fibrils with the finer fibril titer, and the finer fibrils of the cladding filament group have a smaller fibril titer than the fibrils of the core group.

It is preferred according to the invention that the sheath filament group consists of two filament groups of different fibril titers.

In addition to a very good spun-like effect, a filament yarn according to the invention also results in good processing during further processing on knitting machines, twisting machines, weaving machines, etc. The fibrils of the wrapping fitting group, in particular the coarsest fibrils, form alternating spirals along the thread, which envelop the core thread. Any thread forming polymers can be used. Polyamides (PA), polyesters (PES) or their copolymers are preferred, any combinations such as PES-PES, PA-PA etc. being possible.

According to a further characteristic of the invention, the covering group has more fibrils than the core group, preferably in a ratio between 2: 1 and 5: 1. However, it is also possible for the number of fibrils for the core and the covering to be approximately the same.

According to the invention, the coarsest fibrils in the cladding filament group have a fibril titer that is up to 10 times larger than the finer fibrils, preferably 2 to 3 times larger. The titer of core and cladding group together is 50 to 800 dtex, titres between 150 and 500 dtex are preferred.

In order to obtain a core yarn with a good spun-like effect and a good flow, the wrapping group contains 1 to 10 coarse fibrils depending on the titer of the core yarn, with two to three coarse fibrils in the wrapping group for a titer of the core game of 150 to 250 dtex to be favoured. The good properties of this thread are preserved if you have 1 to 10 coarse fibrils in the wrapping group. With an increasing number of coarse fibrils in a core yarn of this type, the fabrics produced become harder to grip.

The invention further relates to a method for producing the above-mentioned filament yarn by spinning two melted spinning masses for core and sheath filament group from thread-forming polymers from separate holes, the group of fibrils after cooling z. B. combined with blown air, provided with spin preparation, wound on yarn carriers and then false twist textured, characterized in that spinnerets are used, the holes for the coarsest and finer fibrils of the sheathing group with different capillary diameters and / or different capillary lengths are distributed so that the holes for the coarsest fibrils are arranged on the side opposite the mouth. If the bores for the coarsest fibrils of the sheathing filament group are not on the side of the spinnerets opposite the cooling air opening, the large deflection of the coarsest fibrils by the cooling air causes contact between the coarsest and finer fibrils, which leads to interruptions in the spinning process and frequent tearing of the thread.

According to one embodiment of the method according to the invention, the core filament and the sheath filament group are spun from the same or different polymers from a separate spinneret pack. The sheath filament group consists of a larger proportion of fibrils with a finer fibril titer and a smaller proportion of fibrils with the coarsest fibril titer, which are obtained through spinneret bores with different capillary diameters and / or different capillary lengths. The sheath filaments are spun at a certain speed X and the core filaments at a certain spinning speed Y, the speed X being equal to or less than the speed Y in most combinations of polymers. These two threads are wound on separate spools. The speed X is usually in the range from 1,000 to 3,500 m / min. The two partially stretched threads are then brought together on a false twist stretch texturing machine in front of the first delivery plant and, in the usual way, heat twist textured, re-fixed, and finally wound up with heat treatment. It is also possible to swirl the textured thread with conventional blowing devices before winding. The procedure according to such a method enables the production of a filament yarn according to the invention which, with a very good spun-like effect, also has a good course of further processing. The schematic view of a yarn produced in this way is shown in FIG.

According to another embodiment, the filament yarn can be produced in a co-spinning process. In this case, the two polymers used for core and cladding are spun simultaneously through separate spinneret holes in a single spinneret pack. According to this inventive method, two melted spinning masses for core and sheath filament group made of different fiber-forming polymers are fed to a common spinneret pack, these two masses for core and sheath filament group are spun simultaneously from separate holes in the common spinneret pack, the groups of fibrils are combined after cooling, e.g. B. to a blended yarn, provides the blended yarn with spin finish and winds the blended yarn on a spool. The coiled yarn is then textured on a false twist stretch texturing machine. Co-spinning speeds of up to 6,000 m / min are possible. A winding speed of approximately 2500 to 4000 m / min is preferred. According to this embodiment, it is also possible, instead of first winding up and then texturing, to produce the yarn in an integrated co-spinning texturing process. In this case, a device is used where spinning and texturing can be carried out in two successive process steps on a single machine without an intermediate winding process. The textured thread can be swirled before winding.

• Figur 1 Eine schematische Ansicht eines Filamentgarnes gemäss der Erfindung mit zwei im Querschnitt verschiedenen Filamentgruppen für die Umhüllung.
• Figur 2 Eine schematische Darstellung einer Maschine zur Durchführung des erfindungsgemässen Co-Spinn-Verfahrens.
• Figur 3 Verschiedene von der Austrittsseite her gesehene Spinndüsen, die in der Vorrichtung von Fig. 2 verwendbar sind.
• Figur4 Schnitte durch Spinndüsen mit verschiedenen Bohrungen für die gröbsten und feineren Fibrillen der Umhüllungsfilamentgruppe.

The invention will now be explained in more detail with reference to the accompanying drawings. Show it

• Figure 1 is a schematic view of a filament yarn according to the invention with two different cross-section filament groups for the sheath.
• Figure 2 is a schematic representation of a machine for performing the co-spinning process according to the invention.
• Figure 3 Various spinnerets seen from the exit side, which can be used in the device of Fig. 2.
• Figure 4 cuts through spinnerets with different holes for the coarsest and finer fibrils of the wrapping filament group.

As shown in FIG. 1, the filament yarn of the invention has a core filament group 1, which consists of several individual fibrils 3, and a sheath filament group 2, which consists of a coarse fibril 4 and finer fibrils 5. As can be seen from FIG. 1, the core fibrils 3 have a larger titer than the finer sheathing fibrils 5. The number of core fibrils is also smaller than the number of sheathing fibrils. The fibrils 4 and 5 form spirals along the thread, which are wrapped around the core. Fig. 1 also explains the good spun-like effect of these threads, which results from the longer, protruding fibrils of the wrapping group, which gives a natural fiber-like appearance and a pleasant feel to the fabric produced. The use of coarser fibrils, while maintaining this good effect, allows these threads to run well during further processing. 1 also shows that the fibrils of the wrapping group are longer than the fibrils of the core group, wherein the percentage difference in length of the wrapping and core can be used as a measure of the spun-like effect. Usually this difference in length is between 5 and 25 _% .

The device in Fig. Enables the filament yarns of the invention to be produced in a co-spinning process with two filament groups of different cross-section for the sheathing group. Two different polymers B and C are fed in the molten state through separate feed lines 6 and 7 to a common spinneret pack 8. This spinneret pack has small and, for example, two larger bores through which polymer C is spun and other bores through which polymer B is spun. Thin single threads 9 and thick single threads 10 made of polymer C, which together form the sheathing group, and the single threads 11 made of polymer B, which form the core group, emerge from the spinneret.

These three single thread groups are combined. Between the union point 13 and the spinneret pack 8, the individual threads are cooled, for. B. by means of air that exits through the cooling air window 12. The combined filament yarn is then provided with a spinning preparation by means of the roll 14 and finally wound onto a spool 15. To make a filament yarn in accordance with the invention, the spun yarn must be textured on a false twist stretch texturing machine. This texturing of the filament yarn is carried out in the usual way.

3a to 3c show various spinnerets that can be used in the device of FIG. 2. As already mentioned above, the co-spinning process of the invention uses a spinneret whose bores are distributed in such a way that the larger bores 25 in FIGS. 3a and 3b for individual threads 10 of the wrapping group in FIG. 1 on the side opposite the cooling air direction A. the spinneret are arranged. The direction of the cooling air is represented by the arrow A in FIGS. 3a to 3c. The arrangement of the remaining bores 24 of the sheathing group, which form the finer individual threads 9 made of polymer C in FIG. 2, and the arrangement of the bores 23 of the core group, which form the individual threads 11 made of polymer B in FIG. 2, can be divided into two halves of the circle (FIG 3a) or distributed in concentric circles (Fig. 3b).

3c shows a spinneret with different areas for the arrangement of the spinneret holes. The semicircular area 28 on the side of the spinneret opposite the cooling air orifice contains the larger holes for the polymer C sheathing component. Area 27 contains the smaller holes for the polymer C sheathing component, while area 26 contains the spinneret holes for the polymer B core component . In addition to the arrangements of the spinneret holes shown here, further arrangements of the spinneret holes are also possible.

4a and 4b show sections through spinnerets with different bores for the coarsest and finer filaments of the sheath filament group. These bores usually consist of a pilot hole 31 and a capillary bore 32. The titer and cross section of the fibrils emerging from the bores are determined by the dimension of the capillary bore 32. 4a shows 2 bores with the same capillary length L1 and different capillary diameters, fine fibrils emerging from the small diameter D1 and coarse fibrils emerging from the large diameter D2. 4b shows 2 bores with the same capillary diameter D3 and different capillary lengths, fine fibrils emerging from the bore with the large capillary length L3 and coarse fibrils from the bore with a small capillary length L4.

The advantages of the invention are explained in more detail with the aid of the following examples. The examples are not to be interpreted in a restrictive sense.

Comparative Examples 1 and 2

These experiments describe the production and processing of known threads, produced according to the prior art, from a core filament group and a sheath filament group.

Polyethylene terephthalate granules were melted on a conventional spinning machine and extruded through a spinneret, then cooled with blown air, converged, provided with a preparation and then wound onto a spool. Two experiments were carried out, each with a core filament group and a sheath filament group, using different polymers, titers, fibril numbers and spinning speeds. In experiment 1, both filament groups were made from polyethylene terephthalate A, while in experiment 2, the core filament group was made from polyethylene terephthalate with an addition of sodium salt of dimethyl sulfoisophthalate B. In both tests, the core thread and the wrapping thread were processed together on a known false twist stretch texturing machine by bringing the core thread and the wrapping thread together before the first delivery unit. In both experiments, at least 36 textured turkeys were produced. The percentage length difference between the core thread and the covering thread was measured. 36 textile bobbins each from a test were simultaneously processed into a knitted fabric on a MAYER OV 36 experimental circular knitting machine, the number of machine shutdowns per kilogram of knitted thread being ascertained. The spun-like effect of the fabric was assessed on the knitted fabric. Table 1 summarizes the most important process features for spinning, texturing and further processing, as well as the most important thread properties of tests 1 and 2.

The further processing properties of these two comparative tests on the circular knitting machine are completely inadequate. Such threads are considered to be intolerable for processing. These tests also show that the improvement in the spun-like effect in test 2 also results in a deterioration in the number of stubs / kg.

Examples 3 to 5

These examples show the production of filament yarns according to the invention according to the first embodiment and their improved processing properties.

Three different threads were produced, the same core thread as used in test 2 being used for all three threads, since this enables the advantages of the invention to be impressively illustrated. During the production of the wrapping threads, care was also taken to ensure that the production conditions from test 2 could possibly be adopted. To produce the sheath filaments of Examples 3, 4 and 5 according to the invention, polyethylene terephthalate granules were melted, extruded through various spinnerets, cooled, converged, provided with a preparation and wound up. The spinneret for the sheath filaments of Example 3 had 35 capillary bores with a diameter of 0.23 mm and 1 capillary bore with a diameter of 0.34 mm. In Example 4, the spinneret had 34 capillary bores with a diameter of 0.23 mm and 2 capillary bores with a diameter of 0.34 mm. In example 5, spinnerets with 26 capillary bores with a diameter of 0.23 mm and with 4 capillary bores with 0.34 mm were used. The large diameter capillary bores were each arranged on the side opposite the cooling air side.

These wrapping threads were textured with the core threads with the same setting of the false twist stretch texturing machine as in the production of test 2. Again, examples 3, 4 and 5 each produced at least 36 texture yarn bobbins and processed them on the same experimental circular knitting machine. Table 2 summarizes the most important process features and properties of Examples 3, 4 and 5.

For examples 3, 4 and 5 according to the invention, these examples show significantly improved processing properties on circular knitting machines compared to tests 1 and 2, with a very good processing result being achieved especially for example 4. The significant improvement in the further processing properties of the yarns according to the invention could also be found in the processing of these yarns on weaving preparation machines and weaving machines. It should also be noted that this good result could be achieved without impairing the very good spun-like effect.

Examples 6 and 7

These examples demonstrate the manufacture of other filament yarns of the invention.

In Examples 6 and 7, the same polymers as in the preparation of Examples 3 to 5 were used to produce the core and sheath filament group. The core thread had a titer of 123 dtex for both examples and had 13 fibrils. In Example 6, the covering thread consisted of 38 finer and 2 5.2 times coarser fibrils. In Example 7, the sheath filament group had 38 finer and 2 2.2 times coarser fibrils. In both examples 6 and 7, the core and sheath filament groups were each stretch-textured together, a highly elastic, intermingled textile yarn being produced. Before winding, two threads were shed, whereby a texture yarn with a titer of 460 dtex was obtained for both examples. The yarns of Examples 6 and 7 showed a very good spun-like effect, had a length difference between the core and sheath thread of 20% and caused considerably less difficulties in the further processing into fabrics than in the comparative tests.

Example 8

In Example 8, the core thread consisted of polyhexamethyl adipamide, which was spun at a spinning speed of 4200 m / min to a thread with a titer of 98 dtex and 17 fibrils. The covering thread consisted of polyethylene terephthalate, which was produced at 2000 m / min and had 34 fine and 2 coarse fibrils with fibril titers of 4.0 and 10.0 dtex. Core and wrapping threads were stretch-textured together. The filament yarn obtained had a length difference between the core and sheath thread of 18% and a titer of 175 dtex. The yarns produced according to this example also had favorable processing properties on circular knitting machines with a good spun-like effect.

Example 9

This example shows the production of filament yarn according to the second embodiment of the method according to the invention.

On a co-spinning line, molten polyethylene terephthalate with an addition of sodium salt of the sulfoisophthalic acid dimethyl ester for the core thread and molten polyethylene terephthalate for the sheath thread were fed to a common spinneret pack with separate lines and spun out of separate holes to form a blended yarn. The arrangement of the spinneret bores was of the same type as shown in Fig.3a. The core thread had 12 fibrils and accounted for 40% of the mixed yarn titer. The sheath yarn, the 60% of the Mischgarnt ⁱ ters constituted, was comprised of 34 fine and coarse fibrils with 2 Fibrillentitern of 3.9 and 8.6 dtex, which were obtained from capillary bores of different diameters. After cooling, the fibrils were converged, provided with spin finish and finally wound up at 3100 m / min. The titer of the mixed yarn was 250 dtex. The yarn was submitted to a false twist machine and textured with a draw ratio of 1.35. The length difference between the core and sheathing thread was 12%. The yarn was characterized by good processing properties when knitting, twisting and weaving and gave fabrics with a good spun-like effect.

Claims (14)

1. False-twist-textured filament yarn of synthetic polymers, comprising a core filament group (1) and a sheath filament group (2) on the outside of and partially wrapped around the core, the two groups of filaments being produced from the same or different polymers, characterized in that the sheath filament group comprises at least two filament parts (4, 5) with different fibril deniers, the smaller part of the sheath filament group (2) including fibrils with the coarset fibril denier and the larger part of the sheath filament group (2) including fibrils with the finer fibril denier, and the finer fibrils (5) of the sheath filament group (2) having a finer fibril denier than the fibrils of the core group (1).

2. False-twist-textured filament yarn according to claim 1, characterized in that the sheath filament group (2) comprises two filament parts (4, 5) with different fibril deniers.

3. False-twist-textured filament yarn according to claim 1 or 2, characterized in that the synthetic polymers used are polyamides, polyesters or their copolymers.

4. False-twist-textured filament yarn according to claims 1 to 3, characterized in that the sheath group (2) has more fibrils than the core group (1).

5. False-twist-textured filament yarn according to any of claims 1 to 4, characterized in that the coarsest fibrils (4) of the sheath filament group (2) have a fibril denier up to 10 times greater than the finer fibrils (5).

6. False-twist-textured filament yarn according to any of claims 1 to 5, characterized in that the combination of core and sheath groups (1, 2) has a denier of 50 to 800 dtex.

7. False-twist-textured filament yarn according to any of claims 1 to 6, characterized in that the number of the coarset fibrils (4) in the sheath group (2) is between 1 and 10.

8. False-twist-textured filament yarn according to any of claims 1 to 7, characterized in that the difference in length between the core filament group (1) and the sheath filament group (2) is between 5 and 25 %.

9. False-twist-textured filament yarn according to any of claims 1 to 8, characterized in that the core and sheath filament groups (1, 2) contain entangled filaments.

10. Process for manufacturing a filament yarn according to any of claims 1 to 9, in which two molten masses for core and sheath filament group of fiber forming polymers (B, C) are spun from separate bores, the groups of fibrils (9, 10, 11) are combined after cooling, for instance with blown air, provided with spinning preparation, wound on a spool (15) and subsequently false-twist-textured, characterized in that spinning nozzles are used in which the bores for forming the coarsest and the finer fibrils (4, 5) of the sheath group (2) with different capillary diameters (D" D₂) and/or capillary lengths (L₃, L₄) are so distributed that the bores (25) for the coarsest fibrils (4) are arranged on the side opposite to the blowing outlet (A).

11. Process according to claim 10, characterized in that two different molten spinning masses are spun from a common pack (8) of spinning nozzles and the combined groups of fibrils are wound after cooling on a sole spool (15).

12. Process according to claim 10, characterized in that two identical or different molten spinning masses are spun, each one from a separate pack of spinning nozzles and the combined groups of fibrils are wound, after cooling, on two different spools and are false-twist-textured together.

13. Process according to any of claims 10 and 11, characterized in that the combined groups of fibrills are directly fed after cooling, with omitting of winding, to a false-twist-device.

14. Process according to any of claims 10 to 13, characterized in that the core and sheath filament groups (1, 2) are entangled.

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