EP0022065B2 - 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 core filament group forming a core and a sheath filament group arranged on the outside of the core and partially enveloping the core, the two filament groups consisting of the same or different polymers. The invention further relates to a method for producing the above-mentioned filament game.

For some years now, there has been an increasing interest in synthetic filament games that are similar to natural fiber games. The better this resemblance to natural fiber games, the better the so-called "spun-like effect". Kem wrapping threads have become more important in recent years, since 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 games 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. This process can be used to make Kemgame with a good spun-like effect, but if you want to process this Kemgame on a knitting machine, for example, big problems arise from frequent machine shutdowns. The presence of protruding filaments in the wrapping thread causes a great restraint when knitting, which must be overcome in order to continue the knitting process. Since large restraining forces lead to defects in the knitted goods produced, parking devices are attached to the knitting machines which shut down the machine when large restraining forces occur. A large number of shutdowns, as they occur with these core games, are not economically viable for the processor.

On the other hand, DE-OS 1915 821 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 sheathing component consists of 75 den / 2 threads or 96 den / 2 threads. DE-GM 77 34 062 describes a voluminous, false-twist textured filament gamm 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 19 15 821 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 retention force 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.

This object is achieved according to the invention in that the sheath filament group consists of at least two filament subgroups, the filaments of which differ in terms of their single titer and their cross section, with a) the one filament subgroup comprising between 1 and 10 sheath filaments with the coarsest single titer in the filament yarn which is up to 10 times coarser than that of the sheath filaments of the other filament subgroup and these coarser sheath filaments compared to the sheath filaments with the finer single titer are in the minority, and b) the finer filaments in the sheath filament group in the majority have a smaller single titer than the filaments of the core filament group, and that c) the filaments of the sheath filament group in the textured yarn are between 5 and 25% longer than the filaments of the core filament group.

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

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, double machines, weaving machines etc. The filaments of the wrapping filament group, in particular the coarsest filaments, 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 sheathing group has more filaments than the core group, preferably in a ratio between 2: and 5: 1. However, it is also possible for the number of filaments for core and sheathing to be approximately the same.

According to the invention, the coarsest filaments of the cladding filament group have a filament titer that is up to 10 times larger than the finer filaments, 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 kemgam with a good spun-like effect and a good process, the contains Wrapping group 1 to 10 coarse filaments depending on the titer of the core game, with two to three coarse filaments in the wrapping group being preferred for a titer of the core yarn of 150 to 250 dtex. The good properties of this thread are retained if you have 1 to 10 coarse filaments in the sheathing group. With an increasing number of coarse filaments in such a core, the fabrics produced get a harder grip.

The invention further relates to a method for producing a false twist stretch textured filament yarn, wherein two melted spinning masses for the core filament group and the sheath filament group are spun from thread-forming polymers from separate bores, the filament groups are combined after cooling by blowing air, provided with spinning preparation, wound onto yarn carriers and then false twisted. Round spinnerets are used, the bores for the coarsest and finer filaments of the sheath filament group with different capillary diameters and / or different capillary lengths are distributed such that the bores for the coarsest filaments of the sheath filament group are arranged on the side opposite the blow opening.

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 cladding filament group consists of a larger proportion of filament with a finer filament titer and a smaller proportion of filament with the coarsest filament 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 drawn threads are then brought together on a false twist stretch texturing machine in front of the first delivery plant and, in the usual way, are heat-treated with false twist stretch texturing, re-fixed, and finally wound up. 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 game 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 game produced in this way is shown in FIG. 1.

According to another embodiment, the filament yarn can be produced in a co-spinning process. In this case, the two polymers used for the core and coating are simultaneously spun through separate spinneret holes in a single spinneret pack. According to this process according to the invention, two molten 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 bores of the common spinneret pack, and the groups of filaments are combined after cooling, e.g. B. to a mixed game, provides the mixed yarn with spin finish and winds the mixed yarn on a gam carrier. The wound mixed 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.

• Figur 1 Eine schematische Ansicht eines Filamentgames 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.
• Figur 4 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 game according to the invention with two different 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 sheath filament group.

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

The device in Fig. 2 enables the filament yarns of the invention to be manufactured in a co- Spinning process with two different filament groups 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 individual threads 9 and thick individual 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 groups of individual threads 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 spin finish 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 game 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 sheathing group in FIG. 2 on the side opposite the cooling air direction A. Side of 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 .3a) or be distributed on 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 bore 31 and a capillary bore 32. The titer and cross section of the filaments emerging from the bores are determined by the dimension of the capillary bore 32. 4a shows two bores with the same capillary length L1 and different capillary diameters, fine filaments emerging from the small diameter D1 and coarse filaments emerging from the large diameter D2. 4b shows 2 bores with the same capillary diameter D3 and different capillary lengths, fine filaments emerging in the bore with the large capillary length L3 and coarse filaments in 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, made according to the prior art, from a core filament group and a wrapping 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, titer, number of filaments 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 experiments, the core thread and the wrapping thread were processed together on a known three-way stretch texturing machine by bringing the core thread and the wrapping thread together before the first delivery plant. In both experiments, at least 36 texture coil coils were produced. The percentage length difference between the core thread and the covering thread was measured. 36 textile yarn bobbins from each experiment 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. The table summarizes the most important process characteristics 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-uke effect in test 2 also results in a deterioration in the number of stops / 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 experiment 2 being used for all three threads, since this clearly demonstrates the advantages of the invention. can be. During the production of the wrapping threads, care was also taken to ensure that the production conditions for 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 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 capillary bores with the large diameter 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 coils 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 particular emphasis being given to a very good processing result could be achieved for example 4. The substantial improvement in the further processing properties of the yarns according to the invention could also be found in the processing of this game 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 further 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 filaments. In Example 6, the covering thread consisted of 38 finer and 2 5.2 times coarser filaments. In example 7, the sheath filament group had 38 finer and 2 2.2 times coarser filaments. In both examples 6 and 7, core and sheath filament groups were each stretch-textured together, a highly elastic, warped textured yarn being produced. Before winding, two threads were fanned, which resulted in a texturam with a titer of 460 dtex for both examples. The game of Examples 6 and 7 showed a very good spun-like effect, had a length difference between the core and sheathing thread of 20% and caused considerably less difficulties in the further processing into fabrics than in the comparative experiments.

Example 8

In Example 8, the core thread consisted of 'polyhexamethyl adipamide, which was spun at a spinning speed of 4,200 m / min to a thread with a titer of 98 dtex and 17 filaments. The covering thread consisted of polyethylene terephthalate, which was produced at 2,000 m / min and had 34 fine and 2 coarse filaments with filament titles 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 mixing gam. The arrangement of the spinneret bores was of the same type as shown in Fig. 3a. The core thread had 12 filaments and made up 40% of the mixed yarn titer. The covering thread, which accounted for 60% of the mixed yarn denier, had 34 fine and 2 coarse filaments with filament titles of 3.9 and 8.6 dtex, which were obtained from capillary bores with different diameters. After cooling, the filaments were converged, provided with spin finish and finally wound up at 3 100 m / min. The titer of the mixed game 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 (8)

1. False-twist-draw-textured filament yam of synthetic polymers, comprising a core filament group (1) forming a core 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 (2) comprises at least two filament sub-groups whose filaments (4, 5) differ in respect of individual denier and cross-section,

. a) one filament sub-group comprising between 1 and 10 sheath filaments (4) with the coarsest individual denier in the yam, having an individual denier up to 10 times coarser than that of the sheath filaments (5) of the other filament sub-group, and these coarser sheath filaments being fewer in number than the sheath filaments (5) with the finer individual denier, and

b) the finer filaments (5) which predominate in the sheath filament group (2) of the other filament sub-group have a smaller individual denier than the filaments (3) of the core filament group (1), and in that

c) in the textured yam the filaments (4, 5) of the sheath filament group (2) are between 5 and 25 longer than the filaments (3) of the core filament group (1).

2. False-twist-draw-textured filament yam according to claim 1, characterized by two filament sub-groups which form the sheath filament group (2).

3. False-twist-draw-textured filament yam according to claims 1 and 2, characterized in that the filaments (3, 4, 5) are made of polyamides, polyesters or their copolymers.

4. False-twist-draw-textured filament yam according to claims 1 to 3, characterized in that the sheath filament group (2) comprises more filaments (4, 5) than the core filament group (1).

5. False-twist-draw-textured filament yam according to claims 1 to 5, characterized in that it has a denier of 50 to 800 dtex.

6. Process for manufacturing a false-twist-draw-textured filament yam according to claims 1 to 5, in which two spinning melts for the core filament group (1) and for the sheath filament group (2) of fibre- forming polymers (B, C) are spun from separate bores and the groups of filaments (9, 10, 11) are combined after cooling with blown air, provided with a spin finish, wound onto a yam package (15) and subsequently false-twist-draw-textured, characterized in that round spinnerets are used in which the bores for the coarsest and the finer filaments (4 or 5) of the sheath filament group (2) with different capillary diameters (D_l, D₂) and/or different capillary lengths (L₃, L₄) are so distributed that the bores (25) for the coarsest filaments (4) of the sheath filament group (2) are arranged on the side opposite the blown air outlet (A).

7. Process according to claim 6, characterized in that the two spinning melts are different and are spun from a common spinneret pack (8) and the combined groups of filaments are wound after cooling onto a single yam package (15).

8. Process according to claim 6, characterized in that the two spinning melts are identical or different and are each spun from a separate spinneret pack and the combined groups of filaments are wound after cooling onto two different yam packages and are false-twist-draw-textured together.

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