Microfiber

Abstract

The present invention relates to a high-tenacity cellulosic regenerated fiber with an individual fiber titer of between 0.6 and 0.9 dtex and yarns and planar textile structures which contain regenerated fibers of this kind.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates to a high-strength cellulosic regenerated fiber with a single fiber titer of between 0.6 and 0.9 dtex and yarns and planar textile structures which contain regenerated fibers of this kind.[0003]2. Description of the Related Art[0004]Today, above all, fibers according to the viscose process are known as cellulosic regenerated fibers and these are produced around the world. For standard applications in the textile and non-wovens sector, fibers are used with an individual fiber titer of between 0.9 and 16 dtex. Fibers with a smaller individual fiber titer are normally designated as microfibers whereby the expression “microfiber” generally designates fibers with a tire smaller than 1.0 dtex or, depending on the material density, with a diameter of 9 to 10 μm (“Lexikon der Textilveredlung”, H. K. Rouette, 1995, Volume 2, p. 1250 ff; Laufman Verlag, Duelman). Moreover it is known that fabrics of microfib...

AI Technical Summary

Benefits of technology

[0033]Compared to this state of the art, the task was to make a cellulosic fiber available which satisfies today's demands for an economical and ecologically responsible production process as well as for enhanced wear comfort and the improved appearance of the articles of clothing made from this. Moreover, there was a need for extremely fine yarns which could be produced from fibers of this kind at favourable cost.

[0037]The fiber in accordance with the invention is preferably in the form of a staple fiber i.e. it is cut to a standardized length in the course of the production process. Common cutting lengths for staple fibers for the textile area lie between approx. 25 and 90 mm. Only such a standardized length of all of the fibers allows for the non-problematic processing on the machines commonly used in the textile chain today with a high productivity.

[0039]In particular it was surprising that yarns in accordance with the invention could be made using air jet spinning processes with a very high fineness. With the fibers in accordance with the invention, it is possible for the first time to exceed the previously known spinning limits of high-performance spinning processes. This applies equally to the rotor as well as the air jet spinning process and the Murata Vortex spinning process. In the MVS spinning process it is possible for the first time to produce yarns finer than Ne 80 (Nm 135) the yarn count of which allows for trouble-free further processing to textiles. In the rotor spinning process it becomes possible for the first time to spin yarns finer than Ne 65 as a result of using fibers according to the patent application. These yarns of a higher fineness also always display a lower number of thin parts and a higher yarn regularity than yarns of fibers with a coarser titer.

Problems solved by technology

For this reason, it is no longer sufficient today to only process fibers with a small titer without paying attention to the fiber tenacity and above all to the fiber tenacity in a wet state.

The result of this process is neither foreseen for textile applications nor does it appear suitable for this.

They are very non-uniform and thus not suitable for textile applications.

Such spray hole diameters cannot be operated with sufficient production safety in large-scale technical operations since deposits form in a short space of time on the spinning bath side of the spray hole which has a detrimental effect on the regularity of the fiber diameter and the spinning safety and or the entire jet channel is blocked with particles of dirt and thus the fiber titer fluctuates to an even greater extent.

Fine fibers of this kind are no longer suitable in particular for textile applications.

The cuoxam process displays considerable environmental problems and is, therefore, no longer used around the globe except in one or two exceptions.

Nothing is, however, disclosed about the fiber tenacities which can be obtained with this process and the production costs are increased as a result of the special pulp.

However, the fibers obtained in this way reveal irregular tire and fiber length distributions so that they are not suitable for high-quality textile and technical applications.

In so doing, however, irregular titer and fiber length distributions are likewise obtained so that these fibers are also not suitable for high-quality textile and technical applications.

Moreover, the process is extremely complex due to the handling required for the desolvation medium and cannot be carried out in a usual Lyocell production line.

To sum up the state of the art therefore, only reveals fine to ultrafine cellulosic fibers, which were made with processes which do not make sense either economically and / or ecologically, have no adequate tenacity and / or there are no details about this or they cannot be used for textile purposes as a result of their means of production.

One considerable disadvantage of the ring spinning process is, however, its low productivity which can be traced back to the technology of the ring spinning process.

Due to the basic technological principles of the ring spinning process—the productivity of this spinning process is determined by the extent of the yarn twist and the spindle speed—the costs of yarn production increase significantly as the yarn fineness increases.

The production of fine or very fine yarns using the ring spinning process is, therefore, extremely cost-intensive.

Compared to the ring spinning process, the rotor spinning process reveals the following disadvantages due to the basic technological principles of yarn production:a) the rotor spinning process requires a significantly higher fiber number in the yarn cross-section than the ring spinning process.

Due to the basic technological principles named above, the rotor spinning machines are, however, not able to produce fine yarns with the same fineness and strength as ring spinning machines

The cellulosic microfibers described before are not suitable for processing in high-performance spinning processes due to their relatively low absolute fineness.

For this reason it was not possible until now to produce super fine yarns from these fibers, which are required to produce the light-weight textiles of cellulosic fibers which are increasingly in demand on the market, using modern high-performance spinning processes.