阅读说明：本技术 莱赛尔纤维丝束、其制造及用途 (Lyocell fibre tow, its production and use ) 是由 A·居特勒 R·D·杰文斯 P·L·普罗伯特 于 2020-03-20 设计创作，主要内容包括：本发明涉及用于牵切、精纺或半精纺纺纱的卷曲的莱赛尔丝束,其制造和用途。(The present invention relates to crimped lyocell tow for use in stretch-breaking, worsted or semi-worsted spinning, its manufacture and use.)

1. Lyocell tow for use in stretch-break, worsted or semi-worsted spinning, characterised in that the individual filaments are crimped and the filament titre is in the range 0.8 to 1.4 dtex, and the tow has a titre between 60 and 160 ktex and a length between 1,000 and 10,000 m.

2. Lyocell tow according to claim 1 wherein the tow is provided with a finish suitable for stretch breaking and subsequent worsted and semi-worsted processing.

3. Lyocell tow according to claim 1 wherein the fibres in the tow have a cross-linked surface.

4. A process for the manufacture of lyocell tow for use in stretch-breaking, worsted and semi-worsted spinning, characterised in that a lyocell full-length tow band which has been coagulated, washed and dried is:

a. split into (m + 1) primary sub-tows by m primary guides,

b. all of the primary sub-tows are passed together through a crimper, where they optionally may be crimped together,

c. at least m primary sub-tows are cut to a length of between 1,000 and 10,000 m and then woven into a container.

5. The method of claim 4, wherein,

a. m is 1, m is a linear chain,

b. the primary sub-strands are woven into a container, and

c. the remaining tow is further chopped into chopped segment fibers having a length of between 20 and 60 mm.

6. The method of claim 5, wherein the primary sub-tows have a tow denier of between 60 and 160 ktex and the remaining tows have a tow denier in excess of 300 ktex.

7. The method of claim 4, wherein

a. m is more than 1, and m is more than 1,

b. between step a and step b, all the primary sub-tows are split into (n + 1) secondary sub-tows by n secondary guides, and

c. the secondary sub-tows are woven into a container.

8. The process according to claim 7, wherein the primary sub-tows are divided into 3 or more (preferably up to 6) secondary sub-tows, preferably 4 secondary sub-tows.

9. The method of claim 7, wherein all secondary sub-tows from a primary sub-tow are co-woven into a container.

10. The process of claim 9, wherein in subsequent process steps, all secondary sub-tows originating from one primary sub-tow are pulled together out of a container, separated and collected in separate containers.

11. The method of claim 7, wherein

a. The primary sub-tows have a tow titer of between 180 and 600 ktex,

b. the secondary sub-tows have a tow titer of between 60 and 160 ktex.

12. Use of lyocell tow according to claim 1 for the manufacture of a blended yarn, wherein the lyocell tow is blended with one or more fibre types from the group consisting of wool, other animal hair, silk, flax, acrylic, polyester, nylon and polypropylene.

13. Use according to claim 12, wherein the yarn is used for the manufacture of circular and jersey fabrics for sweaters, T-shirts, tops, woven shirts and smocks, dressed women and men's coats, dresses and skirts.

14. Spun yarn comprising or consisting of lyocell fibres having a fibre titer between 0.8 and 1.4 dtex and an average staple fibre length of essentially more than 70 mm.

Prior Art

Viscose-type and modal-type man-made cellulose fibers are produced according to the viscose process. In recent years, the "amine oxide process" or "lyocell process" has been established as an alternative to the viscose process, in which cellulose does not form derivatives but is dissolved in an amine oxide organic solvent, in particular N-methylmorpholine-N-oxide (NMMO).

In said process, the cellulose solution is usually extruded through a shaping tool, whereby it is shaped via an air gap, the shaped solution entering a precipitation bath, in which the shaped bodies are obtained by precipitation of the solution. Optionally after further processing steps, the shaped bodies are washed and dried.

Cellulose fibres produced from such solutions are called "solvent spun" fibres and have been given the generic name lyocell by BISFA (international rayon standardization office). For example, in US 4,246,221, a process for producing lyocell fibre is described. The amine oxide process produces fibers known for high tensile strength, high wet modulus, and high hook strength.

Man-made cellulose fibers, such as viscose, modal, lyocell and others, are mainly used for cotton-like applications, i.e. in the form of staple fibers having a discrete staple fiber length of about 32 to 60 mm. They are either applied neat or blended with cotton, other man-made cellulosic fibers or synthetic fibers of comparable staple fiber length. However, there are applications that require longer staple lengths, such as blending with wool, acrylic, nylon, or other long staple fibers for worsted spinning. For example, very fine yarns can be produced therefrom. Such applications require special techniques such as spun yarn spinning and also require very specific processability of the fiber, which is not provided by conventional cotton-based fibers.

The conventional method of providing man-made cellulosic fibers for such applications is to cut them into longer staple fiber lengths (i.e., longer than 60 mm) during fiber production and to make yarns using worsted carding, gilling, combing, twisting or roving and spinning process steps. However, the man-made cellulose fibers carded with fine fiber titer and longer staple fiber length increase the number of neps, which is unacceptable in this high-priced market segment. For this reason, most long staple fibers or bias cut products used in worsted carding and combing are not produced at fiber titers of less than 1.7, 2.0 or even 2.4 dtex.

Another method of producing spun yarns from rayon is by stretch breaking. The principle of stretch-breaking is as follows: the tow is gradually drawn to the point of breaking (the tow contains a bundle of substantially parallel filaments that are not individually treated). The fibers break mainly in the last two break zones of a common stretch-breaking machine. It is important to avoid high draft in the earlier zones to avoid early breaking (pre-breaking) of the tow. The product resulting from the breaking process is the so-called "top". At the end of the machine there is a crimper for mechanically crimping the tops to hold them together for the gilling process. The tops can be blended with wool, acrylic, nylon, or other long staple fibers at the gillbox for worsted spinning.

However, no suitable lyocell filaments are known for stretch breaking.

Problem(s)

In view of the prior art, the problems to be solved are: lyocell tows (pure or blended with other fine fibers) suitable for making fine worsted or semi-worsted yarns are provided, as well as methods of producing such tows on a commercial scale.

Description of the invention

It is therefore an object of the present invention to provide lyocell tow for use in stretch-break, worsted or semi-worsted spinning wherein the individual filaments are crimped and the filament denier is in the range of 0.8 to 1.4 dtex and the tow denier is between 60 and 160 ktex and the length is between 1,000 and 10,000 m. In most cases, the tow length may preferably be between 1500 and 5000 m.

Worsted spinning allows the production of yarns with different aesthetics in hand, feel, drape and overall appearance compared to chopped strand or cotton based textile fabric products. A much lower twist multiplier is typically used for such yarns because for worsted spinning, a much higher average fiber length is used. This provides a very soft and luxurious product that is well appreciated by downstream consumers. Because of the higher tenacity, finer yarn counts with lyocell than with viscose are possible; worsted spinning of finely divided specialty fibers in the specified range is only possible using stretch-break conversion techniques, since long fibers in the more finely divided specialty range can produce many neps if processed through worsted carding and combing process routes. Only if fine and micro lyocell tows are produced, such products can be produced in the future in lyocell and lyocell blends ("micro" meaning fibre deniers of less than 1.0 denier, i.e. less than 1.1 dtex). Future production of such fine and miniature lyocell tows will enable the production of even finer, higher quality worsted spun yarn counts for 100% lyocell and lyocell blended with other fibres.

In a preferred embodiment of the invention, the lyocell tow according to the invention is crimped, although in principle uncrimped tows may also be used for stretch breaking. To date, there is no crimped tow of man-made cellulose fibers.

With the arrangement according to the invention as described above, the skilled person would expect that even after splitting the tow by the primary and secondary guides, some of the filaments of a sub-tow will tend to attach to adjacent sub-tows. Such attachment would make it impossible to properly weave in and out several tows of separated molecules in the same container. This may of course occur in the uncrimped sub-tows. It was surprisingly found that by applying the crimp in the manner according to the invention, the correct braiding and removal of several bundles of split sub-strands in the same vessel takes place without any problems.

In another preferred embodiment of the invention, the lyocell tow according to the invention is provided with a finish suitable for stretch breaking and subsequent worsted and semi-worsted processing. Particularly in the embodiment further described below, which is called "single split", finishing types suitable for both chopped strand fibers and worsted spun fibers may be applied to the lyocell line simultaneously, as separate finishing baths for both product types incur more cost and may not be feasible.

In a particularly preferred embodiment of the invention, the fibers in the lyocell tow according to the invention have a cross-linked surface. Crosslinking can be carried out by generally known techniques, for example using crosslinking agents having a triazine structure, even more specifically TAHT or NHDT as crosslinking compound. Other suitable molecules may also be used. TAHT is the preferred crosslinking agent if the fibers are intended for use in blends with wool.

The invention incorporates an established method of preparing solvent-spun cellulose according to the lyocell process, in which:

i. cellulose is dissolved in an amine oxide solvent to form a hot cellulose solution,

extruding the hot cellulose solution through a die assembly to form a fully-threaded ribbon of continuous filaments,

passing the tow through a water bath to leach out amine oxides,

the tows originating from the plurality of die assemblies are collected in a filament collection area,

v. treating the tow to meet various process applications,

drying the tow, (full tow band denier of tow may be about 400 to 1100 ktex, determined primarily by washing and/or drying capacity)

Splitting the tow one or more times and crimping (as determined by the end use of the process) in accordance with the present invention,

transport of the crimped or uncrimped tow from the crimper to the next step, i.e. braiding into suitable containers or cutting into chopped length fibers, respectively.

Another object of the present invention is to provide a process for the manufacture of lyocell tow which can be used for stretch-break, worsted and semi-worsted spinning, wherein a coagulated, washed and dried lyocell full tow band is:

a. split into (m + 1) primary sub-tows by m primary guides,

b. all of the primary sub-tows are passed together through a crimper, where they are optionally co-compressible to apply crimp,

c. at least m primary sub-tows are cut to a length of between 1,000 and 10,000 m, preferably between 1,500 and 5,000 m, and then woven into a container.

The crimper may be a gear crimper or a stuffer box crimper, both of which are generally known and known in the art how to operate. A stuffer box crimper is generally preferred. During crimping, dry steam is injected into the stuffer box.

The nip roll pressure, stuffer box pressure, and flow rate of dry steam injection in the stuffer box are adjusted within defined parameters that meet fiber process specifications, wherein the tow then exhibits a fixed memory of the induced splitting.

The material leaving the crimper then consists of the simultaneous, parallel production of two crimped tows. Because the tow has an inherent retention of the splits introduced prior to the crimper, it is easy to separate the final sub-tows again when they are removed from the vessel for further processing. The containers may be cans or cartons or the like, with a typical container capacity of about 300 kg, but they may also have smaller or larger capacities.

Conventional requirements for making commercially suitable stretch broken fibers are, inter alia, uniform and parallel tows, with little breaks or distortion, and very little knots in the tows for clear identification (at most one per package) and excellent weaving of the tows for baling without twist of the tows. Also desirable is an extremely low level of waste (dust, short fibers), i.e., about 20% -30% of any normal cut fiber specification tolerance. By means of the present invention, these requirements can be met.

The first preferred embodiment of the process of the invention, the so-called "single-split" embodiment, comprises the following features:

m is 1, m is a linear chain,

the first sub-strands are woven into a container, and

the second sub-tows are further cut intoStaple fibres having a controlled equal length between 20 and 60 mm.

Another unique and novel feature of this embodiment of the present invention is: the simultaneous, parallel production of two crimped tows for completely different yarn processing paths can be carried out simultaneously during the single split collection.

The individual sub-tows at the desired tow denier for stretch breaking may then be separated and split from the main tow and collected in a container. While the remaining second sub-tow is then cut into staple fiber lengths suitable for conventional carding processes and any other number of different yarn processing routes to meet various fabric end uses. For textile applications, staple fiber lengths between 20 and 60 mm are most common.

Preferably in this embodiment according to the invention, the first sub-tow may have a tow titer of between 60 and 160 ktex, preferably between 70 and 135 ktex. One particular value of the strand denier of the first sub-strand may be 82 ktex. The second sub-tow may have a tow titer of greater than 160 ktex, preferably greater than 300 ktex. The sum of the two sub-tow deniers of course gives the full tow band denier.

A second preferred embodiment of the process of the invention, the so-called "multi-split" embodiment, comprises the following features:

m is more than 1, and m is more than 1,

between step a and step b, all the primary sub-tows are split into (n + 1) secondary sub-tows by n secondary guides, and

the secondary sub-tows are woven into a container.

A plurality of tows to achieve the tow denier required for commercial stretch-breaking machine processing can thus be produced by: the slits are introduced into the full tow in sequence using a finger guide as described above until the full tow is split (see fig. 2) and equally subdivided into tows at the desired tow denier. The present invention therefore significantly reduces the complexity of handling and collecting large quantities of tow and reduces the overall level of process equipment required in a manufacturing environment.

Preferably in this embodiment of the invention, the primary sub-tows are divided into 3 or more (preferably up to 6) secondary sub-tows, preferably 4 secondary sub-tows.

Preferably, all secondary sub-tows originating from the primary sub-tows are co-braided into one container. In a subsequent process step, all secondary sub-tows originating from one primary sub-tow may be pulled out of the container together, separated and collected in separate containers. The containers may be cans or cartons or the like. These containers will then hold the tow at a denier that meets the processing constraints required by commercial stretch-breaking machines.

Preferably, the primary sub-strands have a strand fineness of between 180 and 600 ktex.

Preferably, the secondary sub-tows have a tow titer of between 60 and 160 ktex, preferably between 70 and 135 ktex. One particular value of the strand titer of the first sub-strand is 82 ktex. In a more preferred embodiment of the invention, all the sub-tows exhibit the same titer.

In one embodiment of the invention, the means for transporting the tow at various stages uses conventional means, including rollers and pulling devices.

A very specific aspect of the invention is that, according to the invention, the sub-tows are split from the main tow: once the fresh filaments have passed through the coagulation zone, a predetermined number of spinneret filament bundles are gathered together in the extruded filament collection zone by using a novel noose belt. The noose belt comprises the same cellulose material, lyocell, as the tow produced at the time, and meets the same specifications.

The denier of the filaments comprising the bundles may be in the range of 0.9 to 1.40 dtex, and the denier of the tow per bundle may be in the range of 60 to 160 ktex.

The bundle of filaments with the attached noose tape is allowed to pass through the washing, treatment and drying zones of the process.

After leaving the drying zone, the gathered filament bundle is identified, where it is then introduced into a separating mechanism (see fig. 3) comprising a finger guide (see fig. 4) to separate and break apart the smaller and larger tow bundles. At this stage, the lasso band is cut and removed. The lasso belt procedure is applicable to both single and multi-split embodiments according to the present invention.

Another object of the invention is the use of the lyocell tow according to the invention as described above for the manufacture of a blended yarn, wherein the lyocell tow is blended with one or more fibre types from the group consisting of wool, other animal hair such as cashmere or mohair, silk, flax, acrylic, polyester, nylon and polypropylene. The term "wool" refers substantially only to sheep's wool. However, other suitable fiber types commonly used in worsted spinning may be used. Suitable fibre types are further characterised by suitable fibre lengths, typically greater than 60 mm, up to 150 mm, and fibre titres typically similar to the filament titre of lyocell tow. Depending on the product type and end use, those fibers may have a denier above or below that of the lyocell tow, but in most cases the denier of the lyocell tow will be finer than that of the other fibers.

Blending with other fibers is carried out in the gillbox stage after stretch cutting. Two, three or even four gill passes are typically used. Stretch-breaking converters typically perform stretch-breaking to turn the lyocell tow into lyocell tops. This sliver is preferably then blended with other 100% lyocell slivers at the gill box to average out the differences, maintaining an overall consistent product. The slitters (i.e., sliver makers) would then package the sliver into about 10 kg of can sliver (bump top) after this first stage of carding. These can tops were then collected and packaged into 400-500 kg packages for delivery to a worsted spinning machine. Spinning machines then use can slivers and blend with wool, silk, linen, polyester, acrylic, nylon, etc. in their first carding stage, and do so in the other two or three passes. The blended sliver is then processed into roving using a twisting or roving machine, followed by spinning on a worsted ring frame.

The blending process using stretch-cut or carded and combed worsted tops is essentially the same. Blending is performed by assembling slivers of different fibers onto a creel of a gillbox and then combining and drawing the fibers from the slivers into a blended sliver. Gillboxes usually have 20 or more inlets/feeds on the creel for the sliver, only one outlet, so extensive blending can be allowed. The more stages used for gilling, the better the overall blend. The use of stretch-cut tops generally eliminates the need to use combing to remove the staple filaments. However, using worsted carded tops, the tops are usually combed to remove staple fibers and neps.

The yarn manufactured according to the present invention as described above is mainly used to manufacture circular knit fabrics and jersey fabrics for sweaters, T-shirts, tops (tops), woven shirts and smocks, ladies and men's coats for fine western-style clothes, dresses and skirts.

A further object of the invention is a worsted yarn comprising or consisting of lyocell fibres having a fibre titer between 0.8 and 1.4 dtex and an average fibre length substantially greater than 70 mm. Prior to making the present invention, there was no such yarn that was lyocell. It has not been possible to manufacture yarns, especially spun yarns, with lyocell fibres of such fine, long staple fibres in commercially acceptable quality (i.e. with respect to uniformity, tenacity, level of coarse and fine position defects and neps). Worsted spinning of finely divided specialty fibers in the specified range is only possible using stretch-break conversion techniques, since finer specialty long fibers are found to produce unacceptable amounts of neps if processed through worsted carding and combing process routes. The main product is 50% by weight crosslinked lyocell (such as LENZING)^TMLyocell a100, available from Lenzing Aktiengesellschaft, Lenzing austria) and 50% by weight fine yarn count wornu wool or other animal hair such as cashmere or mohair, although other blend combinations and blends with other fibers are possible. Finer denier and higher tenacity in the cellulosic component compared to previously available productsProperties allow for commercial spinning of finer counts to improve softness, drape, and gloss.

The invention will now be illustrated by way of examples. These examples are not intended to limit the scope of the present invention in any way. The invention also encompasses any other embodiment based on the same inventive concept.

Description of the drawings

Figure 1 illustrates the split-curl segment of embodiment 1; m = 1.

Figure 2 shows the split-curl section of embodiment 2; this figure illustrates an embodiment with 2 primary directors and 11 secondary directors; m =2 and n = 11.

Figure 3 illustrates a possible separation mechanism comprising two finger guides to separate and split the smaller tow bale and the larger tow.

Figure 4 illustrates a finger guide as foreseen in figure 3; the guides can be moved individually to the splitting position. Left panel: view looking at the machine direction; right panel: side view.

Legend:

1 full tow band before splitting

2 Primary guide

3, 3' Primary sub-tows

4 two-stage guider

5, 5' Secondary sub-tows

6 residual tow

7 crimping machine

8 remaining crimped tow

9 crimped Secondary sub-Strand of embodiment 1

10 the collection of crimped secondary sub-tows of embodiment 2, derived from one primary sub-tow.

Examples

Preparation of the sample:

lyocell tow bands are produced according to standard lyocell manufacturing processes described in, for example, US 4,416,698 and EP 1307610B 2. The filament deniers produced according to the examples are as follows.

The tow produced was stretch broken at machine speeds of 100-130 m/min on various stretch breakers from Seydel 682 to Seydel 870. The total draw is in the range of 4.5-5.5 and only small draws of 1.05-1.10 and 1.06-1.20 are used in the first two draw zones. The final zone roller center-to-center distance (rat) settings of the first zone 150-. The draft used and the roll center distance zone settings affect the fiber length distribution results, as would normally be expected for any fiber after draw. Fiber length values were measured using the Almeter and Wira test methods and physical measurements of 50, 300 and 600 filaments. This also affects the end result.

Lyocell tow is also run on NSC Seydel S200 machines at speeds up to 225 meters per minute.

Example 1:

the filament fineness was 1.0 dtex and the tow band fineness was 465 ktex. This tow band was split according to the single split embodiment (fig. 1) into 82 ktex primary sub-tows and 383 ktex residual tows using the apparatus according to fig. 3 and 4. The crimper is a conventional mechanical gear crimper. When the remaining tow was then cut to 38 mm staple fiber length, the primary sub-tows were braided into a container and transferred to a tow-to-top converter for stretch-breaking testing. The tows are uniform and parallel, with less than one knot in the tow per container, and the tows are not twisted.

The resulting fibers showed an average fiber length between 55 and 105 mm with a CV% of 30% -50%. The actual results vary depending on the setup used for stretch breaking and the fiber length test method used (i.e., the physical measurement of fiber length for Almeter, Wira or 50, 300 and 600 filaments). In principle a fiber length of 40-165 mm is obtained, with 15% -40% of the fibers < 40 mm.

Example 2:

the filament titer was 1.25 dtex and the tow band titer was 553 ktex. This tow band was split according to the single split embodiment (fig. 1) into 82 ktex primary sub-tows and 471 ktex residual tows using the apparatus according to fig. 3 and 4. The crimper is a conventional mechanical gear crimper. When the remaining tow was then cut to 38 mm staple fiber length, the primary sub-tows were braided into a container and transferred to a tow-to-top converter for stretch-breaking testing. The tows are uniform and parallel, with less than one knot in the tow per container, and the tows are not twisted.

The resulting fibers showed an average fiber length between 60 and 115 mm with a CV% of 30-50%. The actual results vary depending on the setup used for stretch breaking and the fiber length test method used (i.e., the physical measurement of fiber length for Almeter, Wira or 50, 300 and 600 filaments). In principle a fiber length of 40-165 mm is obtained, with 5% -40% of the fibers < 40 mm.

The slivers produced by stretch cutting have been used mostly for 70%/30% (w/w) blends of (lyocell/acrylic) or 50%/50% (w/w) blends with 1.7 dtex acrylic fiber or with merino wool of about 16.5-17.5 microns. Spun yarns with counts up to 80 Nm have been produced. The yarn test results for tenacity were higher than the equivalent 100% merino wool test results, although the yarn elongation was lower than expected. Commercially acceptable yarns have been produced for plain knit and woven end uses where the product is used in a variety of end uses such as woven shirts, woven suits, sweaters, seamless running shirts, T-shirts, vests, and sportswear for running and hiking. Wool tops from 1.4 dtex lyocell have also been used in carpet development.