Method and device for manufacturing splittable fibers and use thereof

Abstract

The invention relates to a method and a device (2) for manufacturing splittable fibers (1), by means of which it is possible to conduct the melt streams of the two or more mutually incompatible polymer components (A, B) in the melt spinning process in such a way that the flow of one polymer stream around individual polymer streams, or intermingling of the various polymer streams, is prevented, in particular for greatly different weight proportions of the polymer components (A, B).For this purpose, distribution holes (6) are provided upstream from at least one spinning capillary (4), and the cross-sectional area of the at least one distribution hole (6) associated with a particular polymer component (A, B) is adjusted as a function of the volumetric flow of the particular polymer component (A, B).

Description

TECHNICAL FIELD[0001]The invention relates to a method and a device for manufacturing splittable fibers by means of a melt spinning process, using at least two mutually incompatible polymer components, splittable fibers manufactured according to the method, and use thereof.PRIOR ART[0002]Methods and devices are known from EP 0 413 688, U.S. Pat. No. 5,562,930, and FR 2 647 815 for the manufacture of splittable fibers by means of a melt spinning process, using at least two mutually incompatible polymer components. The individual polymer melt streams are led through distribution plates inside a spinning head in such a way that the threads exiting the spinning head consist of multiple elementary threads of the respective polymers which, viewed in the cross section of the thread, are alternatingly positioned.[0003]The use in particular of polyamide 6.6 as one of the polymers entails high costs for the starting material. In addition, this starting material makes it necessary to dry the r...

AI Technical Summary

Benefits of technology

[0010]The object of the invention, therefore, is to provide a method and a device for manufacturing splittable fibers using a melt spinning process, by means of which it is possible to conduct the melt streams of the two or more mutually incompatible polymer components in the melt spinning process in such a way that the flow of one polymer stream around individual polymer streams, or intermingling of the various polymer streams, is prevented, in particular for greatly different weight proportions of the polymer components.

[0018]As a result of the minimum proportion of less than or equal to 20%, preferably less than or equal to 15%, 10%, 5%, or 3% by weight of a component, in particular comparatively expensive polymers such as polyamide 6.6, for example, the costs for the starting materials and end products of multicomponent fibers may be reduced. Furthermore, undesired properties of a component, for example yellowing, may be reduced by use of only a minimum proportion of this component. In addition, significantly decreasing a proportion of polymer and / or the distinct segmentation of the polymer components in the fibers may also enhance the capability for recycling.

[0028]In addition, the desired properties of the multicomponent fibers may be precisely controlled by use of specific weight proportions of the polymers used.

[0035]A further object of the invention is to provide a device for manufacturing splittable fibers, by means of which it is possible to conduct the melt streams of the two or more mutually incompatible polymer components in the melt spinning process in such a way that the flow of one polymer stream around individual polymer streams, or intermingling of the various polymer streams, is prevented, even for greatly different weight proportions of the polymer components. The minimum proportion of one polymer component is in particular less than or equal to 20% by weight, preferably less than or equal to 10% by weight, particularly preferably less than or equal to 5% by weight, very particularly preferably less than or equal to 3% by weight.

Problems solved by technology

The use in particular of polyamide 6.6 as one of the polymers entails high costs for the starting material.

In addition, this starting material makes it necessary to dry the raw material, generates an electrostatic charge during the spinning process, and tends to yellow under the effects of light and heat.

By use of the known methods, however, the weight ratio of the polymer components used may be varied primarily in a proportion of 30:70 to 70:30, since otherwise, separate polymer segments are no longer obtained, and splitting into microfibers is thus difficult or even impossible.

As a result, in extreme cases fibers, although composed of polymers which are actually incompatible, may no longer be splittable by mechanical means, in particular by use of water jets.

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