EP0290926A2 - False-twist textured bulky multifilamentary yarn, method for making it, and its use - Google Patents

Abstract

A false twist textured voluminous synthetic multifilament yarn made of a uniform raw material is described, which consists of at least two filament groups with different, but essentially the same individual denier. The finer single titer is less than 1 dtex, and the total titer of the textured yarn is greater than 100 times the finer single titer. In the method for producing such a multifilament yarn, the draw ratios of the two filament groups are chosen so that the difference between the two draw ratios is less than 0.1, and the joint draw texturing is then carried out at the draw ratio of the filament group with coarser individual titre. Preferred areas of application for the yarn are water-repellent fabrics, clean room clothing and the conductive component in sportswear.

Description

The invention relates to a false twist textured voluminous synthetic multifilament yarn made of a uniform raw material, consisting of at least two filament groups with different, but essentially identical individual titers ET 1 and ET 2. The invention further relates to a method for producing and the use of such a multifilament yarn.

The false twist texturing has proven to be the most cost-effective construction method for endless multifilament yarns with a total titer of less than 200 dtex. With this method, however, it has so far not been possible to produce a lint-free yarn that contains more than about 100 individual capillaries. The finest multifilament yarn made of polyethylene terephthalate (PET), which has previously been commercially manufactured using the false twist process, has the titer 56 dtex f 100. In practice, the following experience applies to fine capillary textured yarns for use in fabrics and knits:
Titer 55f46 non-swirled can generally be used. Titer 55f46 × 2 can only be used as a warp yarn for high-performance looms when interlaced due to insufficient thread purity.
Titer 55f46 × 3 is also too tangled too fluffy for use as warp yarn in weaving.
80 titer 55f46 × 4 can only be used for particularly insensitive areas.
Multifilament yarns with a higher total denier, for example 150 dtex f 250, are preferably bulked using the air texturing method. Fabrics, knitwear and knitwear made exclusively from fine untwisted multi Filament yarns with a single titer smaller than 1 dtex exist, have too little stance and are too "lobed" to handle. For this reason, for example, in suede-like fabrics, the chain is preferably made from coarser and only the weft from finer individual capillaries. The same applies to the lower and upper chain for knitwear.

EP-OS 0 124 869 discloses a water-repellent, high-density textile fabric in which, according to some exemplary embodiments, a synthetic multifilament yarn made from two filament groups of different individual deniers is used, the individual denier of one filament group being extremely fine and the individual denier of the other filament group being significantly coarser . However, this is not a false twist textured multifilament yarn. Rather, the unification of the finer and coarser filament groups takes place, among other things. when triggering their different shrinkages. This process is therefore complex, both in its implementation and in the finishing of the fabrics made from these yarns, since they have only a minimal shrinking force.

Furthermore, numerous methods for producing a synthetic multifilament yarn from a uniform raw material, consisting of at least two filament groups with different, but essentially identical, individual titer are already known. In these processes, the two filament groups are jointly stretch-textured after spinning using the false twist process. The two filament groups are pre-oriented differently so that the draw ratio of the filament group with coarser single titer is smaller than that of the filament group with finer single titer. The draw ratio is to be understood as the draw ratio at which the draw texturing of each of the individual filament groups is a maximum tensile force expansion of 25% would result (compare e.g. DE-OS 23 08 031, Lenzinger reports, issue 47, 1979, p. 67f, EP-OS 0 022 065, man-made fibers / textile industry, 37th / 89th year, Febr. 1987, p 107f). In these processes, however, filament groups of very different draw ratios are combined, with the aim of creating loops or protruding fiber ends by under or over drawing a filament group during the texturing to impart fiber character to the multifilament yarn.

Finally, methods are known in which a false-twist textured yarn, which preferably consists of bundles with different capillary thicknesses, is given a fiber-yarn-like character in that it is rotated alternately in the S and Z directions due to the extremely low outlet tension during texturing and the associated slipping of the twist (see DE-OS 29 34 762 and EP-OS 0 022 065). However, similar to staple fiber yarns, these yarns have only a small volume due to their high twist and are unsuitable for the intended use.

The invention has for its object to provide a false twist textured voluminous synthetic fine capillary, lint and loop free and inexpensive to manufacture multifilament yarn and a method for producing such a multifilament yarn.

To solve this problem, a false twist textured voluminous synthetic multifilament yarn made of a uniform raw material, consisting of at least two filament groups with different, but essentially the same single titer ET₁ and ET₂ according to the invention characterized in that for the finer single titer ET₂ <1 dtex and for the total titer T. of the textured yarn T> 100 × ET₂ applies.

By selecting the individual titers of the two filament groups, it is possible to overcome the "lobed" grip of fabrics that consist only of multifilament yarns with an individual titre smaller than 1 dtex. Preferably, only two different spun filament groups are presented for joint simultaneous stretch texturing. The filament yarns according to the invention are bulky. They have no alternating S and Z filament groups or core and sheath filament groups. Preferably (but not necessarily) the filament yarns according to the invention are twist-free.

If the individual capillaries of both filament groups have a round cross section, expediently applies to the individual titers ET 1 and ET 2 3 <ET 1 / ET 2 <8. In this way, despite the fine single titre ET 2 <1 dtex according to the present invention, sufficient stiffness of the fabric to be produced from this multifilament yarn can be achieved .

According to a particular embodiment of the present invention, a round cross-section is used for the individual capillaries of the finer filament group and a profiled cross-section, for example in the form of a pronounced Y, for the individual capillaries of the coarser filament group. Since the profiled cross-section already gives the multifilament yarn increased rigidity, the titer ratio 1.5 <ET₁ / ET₂ <4 should be selected in this case.

The synthetic polymers used can be pure or modified polyesters or polyamides. The polyesters can be subjected to direct esterification or transesterification and after following condensation. Instead of ethylene glycol, other diols, such as 1,3-propanediol, 1,4-butanediol, etc., and other dicarboxylic acids, such as isophthalic acid, adipic acid, etc., can also be used instead of terephthalic acid. The polyamides can be either type 6 or 6.6 or their copolymers.

• a) die Spinntiter der beiden Filamentgruppen so gewählt werden, daß für den feineren Einzeltiter ET₂ des streck-­texturierten Garnes ET₂ < 1 dtex und den Gesamttiter T des strecktexturierten Garnes T > 100 × ET₂ gilt,
• b) die Verstreckverhältnisse VE₁ und VE₂ so gewählt wer­den, daß VE₂ - VE₁ < 0,1 gilt,
• c) das gemeinsame Strecktexturieren bei dem Streckverhält­nis VE₁ der Filamentgruppe mit gröberem Einzeltiter durchgeführt wird,
• d) und daß die Spannung des Garns nach Verlassen der Tex­turierspindel größer als 0,3 cN/dtex gewählt wird.

A process for producing a synthetic multifilament yarn from a uniform raw material, consisting of at least two filament groups with different, but essentially the same individual titer, in which process the two filament groups are spun and then stretch-textured together in the false twist process, the spinning take-off speeds of the two filament groups between 2500 and 5000 m / min are selected and the two filament groups are differently pre-oriented so that the draw ratio VE₁ of the filament group with coarser single titer is smaller than the draw ratio VE₂ of the filament group with finer single titer, with the draw ratio being understood as the draw ratio in which a draw texturing each of the individual filament groups would give a maximum tensile strength extension of 25%, is characterized according to the invention in that

• a) the spin titer of the two filament groups are selected so that for the finer single titer ET₂ of the stretch-textured yarn ET₂ <1 dtex and the total titer T of the stretch-textured yarn T> 100 × ET₂ applies,
• b) the draw ratios VE₁ and VE₂ are chosen so that VE₂ - VE₁ <0.1 applies,
• c) the joint stretch texturing is carried out at the stretch ratio VE 1 of the filament group with coarser single titer,
• d) and that the tension of the yarn after leaving the texturing spindle is chosen to be greater than 0.3 cN / dtex.

In the method according to the invention, the degree of orientation of the two filament groups and the draw ratio when stretch texturing together (co-texturing) are selected such that the co-texturing involves drawing the two filament groups under essentially the same tension. In this way, in contrast to the previously known cotexturing processes which aim to produce loops or protruding fiber ends, it has been possible to produce a false-twist textured, fine-capillary, lint-free and loop-free multifilament yarn. In addition, the method according to the invention is characterized by low manufacturing costs.

To spin the two groups of filaments, the raw material granules are dried, melted, filtered and pressed through spinnerets in accordance with the generally customary yarn production process. The resulting multifilament yarns are cooled by an air stream, provided with a spin finish, swirled and wound up.

The different pre-orientation of the two filament groups can be achieved by spinning at different spinning take-off speeds on different spinning systems. In this case, the two filament groups are not combined until the stretch texturing.

According to a preferred embodiment of the invention the different pre-orientation of the two filament groups by means of suitable procedural measures at adjacent spinning positions, that is to say with the same spinning take-off speed, so that the two filament groups are combined after preparation and then swirled and wound up together. These procedural measures for a higher pre-orientation of the coarser filament group can consist in profiling the cross-section of the individual capillary. Another possibility is an additional heat treatment of the filament group in question in a tube heated to 80 ° C to 150 ° C, which is attached in the area between the blowing and preparation, such as in EP-OS 0 013 101, examples 5 and 6 and figure 2 described.

Preferred areas of application of the multifilament yarn according to the invention are water-repellent fabrics, clean room clothing and the conductive component in sports clothing. If only one heater is heated during stretch texturing, high-shrinking multifilament yarns are created, which are particularly suitable for the production of fine-pored textile fabrics for rainwear and cleanroom clothing. A yarn according to the invention with a shrinkage <10% at 130 ° C. is suitable for use in double-surface articles which contain a conductive and a sorptive component for reasons of clothing physiology, which is obtained by additionally heating the second heater during stretch texturing.

The procedure for carrying out the method according to the invention will now be explained on the basis of the single figure which shows the relationship between the spinning titer and the draw ratio.

In the figure, the individual titer of the Spinning thread (spinning titer), measured in dtex, applied on a logarithmic scale. The ordinate shows the draw ratio of the filament, starting at 1: 1.0 in the origin.

As is known, a measure of the degree of orientation of a spun fabric is the stretching ratio VE used in the stretch texturing of the outlet speed at the delivery unit 2 to the inlet speed at the delivery unit 1 on the stretch texturing machine. The draw ratio is to be understood as the draw ratio which leads to a maximum tensile force elongation of the draw textured yarn of approximately 25%.

The curves a, b, c shown in the diagram represent the relationship between the draw ratio and the spinning titer, curve a for a spinning yarn with a spinning take-off speed of 4000 m / min with a round cross-section of the individual capillary, curve b for a spinning yarn with a spinning take-off speed of 3000 m / min with a round cross section of the individual capillaries and curve c for a spinning yarn with a spinning take-off speed of 3000 m / min with a Y cross section of the individual capillaries.

It is not surprising that all curves for constant spinning take-off speed meet at the origin of this coordinate system ET = 0.01 → 0 and VE 1: 1.0. It is surprising, however, that the curves for a constant take-off speed prove to be a straight line. This facilitates the selection of suitable filament groups (spun threads) for carrying out the method according to the invention.

As can easily be seen, the diagram allows the spin filament for the two filament groups choose the respective pre-orientation of the filament groups so that their draw ratios meet the condition VE₂ - VE₁ <0.1.

The method according to the invention is now explained in more detail with the aid of examples.

Example I

A spinning thread 1 made of PET is produced with a conveyance of 28 g / min by spinning from 22 round bores at a spinning take-off speed of 4000 m / min. This spinning thread 1 with the titer 70f22 is submitted as a trial to a drawing texturing machine, the drawing ratio of which is set to 1: 1.28 and the iron temperature of which is set to 195 ° C., and is textured at 400 m / min winding speed. The tensile force of the yarn after leaving the texturing spindle is 24 cN. In the subsequent tear test, the following measured values were obtained: tenacity 36 cN / tex, maximum tensile elongation 24%.

In an analogous manner, a spinning thread 2 is produced from the same raw material with a conveyance of 20 g / min, a number of round bores of 88 and a spinning take-off speed of 3000 m / min. After the drawing texturing of the spinning thread 2 on the same drawing texturing machine, at the same temperature and winding speed as the spinning thread 1, but with a drawing ratio of 1: 1.34, the tensile force of the yarn being 23 cN after leaving the texturing spindle, the following measured values result : Fineness 37 cN / tex, maximum tensile elongation 25%.

The draw ratio of the two filaments 1 and 2 differs by 5%, the difference is therefore less than 0.1.

To produce a yarn according to the invention, both spun threads 1 and 2 (filament groups) are used together on one Texturing point textured under the conditions of spinning thread 1. The tensile force of the yarn after leaving the texturing spindle is 51 cN. This creates a loop-free and lint-free, voluminous multifilament yarn with the following properties: tenacity 37 cN / tex, maximum tensile strength elongation 22%, shrinkage of 41% at 130 ° C. The multifilament yarn has a total titer of 116 dtex and contains 88 single capillaries with a single titer ET₂ of 0.6 dtex and 22 single capillaries with a single titer ET₁ of 2.5 dtex.

For illustrative purposes, the data of the filaments 1 and 2 are entered as points A and B in the diagram of the single figure. For all other spun threads with a round cross-section, which are spun on similar lines at 3000 or 4000 m / min, you can see the stretching ratios for each individual titer from lines a and b.

Example II

In this example, single capillaries with a round cross-section are used for the spinning thread 2 with a finer single titer and individual capillaries with a profiled cross-section, for example in the form of a Y, for the spinning thread 1 with a coarser single titer. The data for the two strands 1 (corresponding to point C of the diagram) and 2 are as follows:

The two spinning threads 1 and 2 are spun on side by side spinnerets of the same spinning system, that is to say with the same spinning take-off speed. After this Cooling and preparation of the two previously running spun threads are brought together and swirled together before winding. The combined spun thread thus obtained is stretch-textured under the conditions of the spinning thread 1. The tensile force of the yarn after leaving the texturing spindle is 51 cN. The yarn thus obtained is lint and loop free and has the following properties: tenacity 35 cN / tex, maximum tensile elongation 20%, shrinkage of 45% at 130 ° C. The multifilament yarn has a total titer of 122 dtex and contains 88 single capillaries with a round cross section with a single titer ET₂ of 0.6 dtex and 60 single capillaries with a Y cross section with a single titer ET₁ of 0.9 dtex.

In this embodiment it is also possible to vary the stiffness of the yarn. This will be illustrated using an example III.

Example III

In this example, the stiffness of the yarn is increased according to the points B 'and C' in the figure. For this purpose, spinning pumps with different feed per revolution are used for the spun threads 1 and 2 spun next to one another. The data for the two strands are as follows:

The swirled combined spun thread 1 + 2 is drawn with the draw ratio 1: 1.36 and otherwise at the same temperature and speed as in Example I. textured. The tensile force of the yarn after leaving the texture spindle is 52 cN. The voluminous multifilament yarn thus obtained is lint and loop free and has the following data: tenacity 36 cN / tex, maximum tensile elongation 23%, shrinkage 42% at 130 ° C. The titer is 118 dtex. The multifilament yarn contains 40 individual capillaries with a round cross-section with a single titer ET₂ of 0.8 dtex and 48 individual capillaries with a Y cross-section with a single titer ET₁ of 1.3 dtex.

• 1) durch Fachen der feinkapillarigen Spinnware vor dem Texturieren nicht möglich ist, ein flusenfreies Garn herzustellen;
• 2) auch durch Fachen von fein- und grobkapillarigem tex­turierten Garn nicht möglich ist, ein für die vorge­sehenen Einsatzgebiete geeignetes Garn herzustellen. Dieses Ziel wird somit nur durch die vorliegende Er­findung erreicht.

The following comparative examples show that it

• 1) it is not possible to produce a lint-free yarn by folding the fine capillary spun fabric before texturing;
• 2) it is also not possible to produce a yarn suitable for the intended areas of application by weaving fine and coarse capillary textured yarn. This aim is therefore only achieved by the present invention.

Comparative Example 1

Two spinning bobbins of the spinning thread 2 from Example I with the titer 67f88 are textured together with the draw ratio 1: 1.34 and, moreover, under the conditions described there. A fluffy yarn is created. This result is also obtained when the stretching texture ratio is gradually reduced to 1: 1.28, to 1: 1.24 or to 1: 1.20, i.e. no suitable texturing conditions can be found for this yarn.

Comparative Example 2

The spun threads 1 and 2 described in Example I are simultaneously on two adjacent texturing points under the texturing conditions specified in Example I, namely with the stretching ratios 1: 1.28 or 1: 1.34 textured. This ensures that both capillary bundles are fed with the same tension from the texturing zone of the winding. Despite these optimal conditions, it was not possible to mix both yarns as intensely as required for a suitable warp yarn by swirling in an air stream. Already after the texturing process, the yarn 2 with the fine single titer 0.6 dtex is mixed so intensively that it can no longer be opened in the air stream to the extent necessary for a thorough mixing of the two yarns.

As the examples given show, it is only possible according to the teaching of the present invention to produce flawless, false-twist textured, voluminous (preferably twist-free) yarns with ET₂ less than 1 dtex and greater total titer than 100 × ET₂.

Claims (10)

1. False twist textured voluminous synthetic multifilament yarn made of a uniform raw material, consisting of at least two filament groups with different, but essentially the same individual titer ET₁ and ET₂, characterized in that for the finer single titer ET₂ <1 dtex and for the total titer T of the textured yarn T. > 100 × ET₂ applies. 2. False twist textured voluminous synthetic multifilament yarn according to claim 1, characterized in that 3/7 <T₁ / T₂ <7/3 applies to the total denier T₁ and T₂ of the two filament groups. 3. False twist textured voluminous synthetic multifilament yarn according to claim 1 or 2, characterized in that 3 <ET₁ / ET₂ <8 applies to the individual titers ET₁ and ET₂ with a round cross section of the individual capillaries of both filament groups. 4. false twist textured voluminous synthetic multifilament yarn according to claim 1 or 2, characterized in that for the individual titers ET₁ and ET₂ with a round cross section of the individual capillaries of the filament group with finer individual titers and profiled cross section of the individual capillaries of the filament group with coarser individual titers 1.5 <ET₁ / ET₂ < 4 applies. 5. A method for producing a synthetic multifilament yarn from a uniform raw material, consisting of at least two filament groups with different, but essentially the same individual titer, in particular according to one of the preceding claims, in which method the two filament groups are spun and then ßend in the false twist process together stretch textured, the spinning take-off speeds of the two filament groups between 2500 and 5000 m / min are selected and the two filament groups are differently pre-oriented so that the draw ratio VE 1 of the filament group with coarser individual titer is smaller than the draw ratio VE 2 of the filament group with finer Individual titer, the drawing ratio being understood to mean the drawing ratio in which a drawing texturing of each of the individual filament groups would result in a maximum tensile strength extension of 25%, characterized in that a) that the spin titer of the two filament groups are selected so that T> 100 × ET₂ applies to the finer single titer ET₂ of the stretch-textured yarn ET₂ <1 dtex and the total titer T of the stretch-textured yarn b) that the draw ratios VE₁ and VE₂ are selected so that VE₂ - VE₁ <0.1 applies, c) that the joint stretch texturing is carried out at the stretch ratio VE 1 of the filament group with coarser single titer, d) and that the tension of the yarn after leaving the texturing spindle is chosen to be greater than 0.3 cN / dtex. 6. The method according to claim 5, characterized in that the two filament groups for the purpose of different pre-orientation with different spinning take-off speeds and are only combined during stretch texturing. 7. The method according to claim 5, characterized in that the two filament groups are spun at the same spinning take-off speed with different orientations and are wound together before stretch texturing. 8. Use of the yarn according to one of claims 1 to 4 with a shrinkage of> 10% at 130 ° C for the production of waterproof fabrics or knits. 9. Use of the yarn according to one of claims 1 to 4 with a shrinkage> 10% at 130 ° C for the production of fine-pored fabric or knitwear for clean room clothing. 10. Use of the yarn according to one of claims 1 to 4 with a shrinkage <10% at 130 ° C as a conductive component in the manufacture of sportswear.

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