Biodegradable fibers exhibiting storage-stable tenacity

Abstract

The invention provides a drawn and/or crimped fiber comprising a biodegradable polymer, such as polylactic acid, wherein the drawn and/or crimped fiber exhibits a storage-stable tenacity that does not decrease from an initial tenacity upon manufacture by more than about 10% after storage for 120 days in ambient conditions. The polymer composition used to form the fiber may comprise a softening agent. The fiber can be a drawn and crimped bicomponent fiber that is helically self-crimped and which comprises a first biodegradable polymer component and a second biodegradable polymer component, wherein the first polymer component and the second polymer component exhibit different polymer morphology such that each polymer component will undergo a different extent of longitudinal shrinkage upon application of heat. The outer surface of the fiber may carry a water-repellant coating. The invention also provides a method of forming a drawn and/or crimped fiber exhibiting storage-stable tenacity.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 638,860, filed Dec. 22, 2004, which is incorporated herein by reference in its entirety and for all purposes.FIELD OF THE INVENTION [0002] The invention is directed to fibers comprising a biodegradable polymer and methods of making such fibers. BACKGROUND OF THE INVENTION [0003] The use of nonwoven fabrics has become increasingly prevalent in a number of industries, and in particular, has found increasing usefulness as a component of a variety of consumer products. Exemplary uses for nonwoven fabrics include, without limitation, absorbent personal care products such as diapers, incontinence pads, feminine hygiene products and the like; medical products such as surgical drapes and sterile wipes; filtration devices; interlinings; disposable wipes; furniture and bedding construction; insulating products; apparel and the like. A variety of thermoplastic and thermobon...

AI Technical Summary

Benefits of technology

[0008] The present invention provides a fiber comprising a biodegradable polymer, such as an aliphatic polyester. Exemplary aliphatic polyesters include polyglycolic acid, polylactic acid, polyhydroxy butyrate, polyhydroxy valerate, polycaprolactone, and copolymers thereof. Preferred embodiments of the fiber of the invention exhibit a storage-stable tenacity, meaning tenacity does not decrease from an initial tenacity upon manufacture by more than about 10% after storage for 120 days in ambient conditions. As a result, the present invention provides a fiber comprising a biodegradable polymer that is capable of maintaining a desired level of strength for a longer period of time.

Problems solved by technology

It has been discovered that fibers formed of biodegradable polymers lose strength, in part, due to hydrolytic attack of the polymer by moisture present in an ambient storage environment.

This gradual loss of strength (i.e., tenacity) over time reduces the value and usefulness of the fibers.