Biocomponent fibers with an exterior component comprising polypropylene

Abstract

The present invention relates to bicomponent fibers with improved bonding properties. In particular, the present invention relates to bicomponent fibers comprising an exterior component, which in turn comprises a polypropylene that has been degraded from a first melt flow index MFI1 (measured according to ISO 1133, condition L, 230° C., 2.16 kg) to a second melt flow index MFI2 (measured according to ISO 1133, condition L, 230° C., 2.16 kg), such that the degradation ratio MFI1 / MFI2 is within a well-defined range and such that the second melt flow index MFI2 is in the range from 50 dg / min to 300 dg / min. Further, the present invention relates to nonwovens, composites and laminates comprising said bicomponent fibers. The present invention also relates to a process for making such bicomponent fibers, nonwovens, composites and laminates.

Description

FIELD OF THE INVENTION[0001]The present invention relates to bicomponent fibers with improved bonding properties. In particular, the present invention relates to bicomponent fibers comprising an exterior component, which in turn comprises a polypropylene that has been degraded from a first melt flow index MFI1 (measured according to ISO 1133, condition L, 230° C., 2.16 kg) to a second melt flow index MFI2 (measured according to ISO 1133, condition L, 230° C., 2.16 kg), such that the degradation ratio MFI1 / MFI2 is within a well-defined range and such that the second melt flow index MFI2 is in the range from 50 dg / min to 300 dg / min. Further, the present invention relates to nonwovens, composites and laminates comprising said bicomponent fibers. The present invention also relates to a process for making such bicomponent fibers, nonwovens, composites and laminates.THE TECHNICAL PROBLEM AND THE PRIOR ART[0002]Polypropylene is one of the most widely used synthetic polymers for fibers and ...

AI Technical Summary

Benefits of technology

[0053]The present inventors have also been surprised that the increase in tenacity that was observed on the nonwovens, especially the spunbond nonwovens, of the present invention was not accompanied by a decrease in elongation but on the contrary by an increase in elongational properties. Thus, the present invention allows the production of nonwovens that at the same time have improved tenacity and elongation, and this in machine as well as cross-machine direction.

Problems solved by technology

Frequently, it is not possible to produce fibers or nonwovens having all the desired properties with a single polypropylene and one has to revert to technically more demanding solutions, such as for example bicomponent fibers.

However, fibers and nonwovens comprising polyethylene have the disadvantage that they are more difficult to produce because the processability of polyethylene in fiber spinning is not as good as that of polypropylene.